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    Ad serving limits are a common pain point amongst AdSense publishers. Invalid traffic has been a major theme for Google for the last couple of years and there has been a rise in enforcement action, in an attempt to protect the digital advertising ecosystem from fraud and bad ad experiences.

    Note: This article was originally posted on 14th December 2020 and has been regularly updated show the most up to date information. The most recent substantial update was November 2021

    Seeing the warning that ad serving has been limited in your AdSense account is a concern and can be costly to a publisher. With this guide, we’ll help you understand what to do if your AdSense ad serving has been limited as well as how to prevent this from happening in the first place. Below we will cover various warnings that can appear in your account, including:

    • “The number of ads you can show has been limited”
    • “Ad serving is limited. The number of ads you can show has been limited”
    • “Ad serving limit placed on your AdSense account”
    • “Ad serving is currently limited. Review the issue details and see recommendations about what you can do next”
    • “Temporary ad serving limit placed on your AdSense account”

    Whilst this post doesn’t specifically relate to similar messages in AdMob accounts, the principals are the same so this post will still be relevant to AdMob users as well.

    Had enough of dealing with issues like this? Being a publisher has gotten more complex. It is no surprise that more and more publishers want to focus on content and traffic and let someone else deal with problems like GDPR, Policy, Yield Management and Optimisation. If you like the sound of going back to growing your business and leaving ad headaches to the specialists, Click here to find our more about how OKO can help.

    What are ad serving limits?

    Ad serving limits are account-level enforcements that restrict the number of ads that your AdSense account can show. Limited ad serving impacts publishers’ earnings directly because fewer ads are shown to users which means fewer clicks and less revenue as a result.

    Enforcement action is usually temporary, lasting around 30 days, but this can take longer under certain circumstances. There are usually two reasons why Google might place ad serving limits on an AdSense account, and the one that applies to you will be shown under “Issues” alongside the account status notice:
    Account being assessed: Google is monitoring your traffic profile in order to assess the quality of your website traffic and detect any invalid activity.
    Invalid traffic concerns: Google has detected invalid traffic concerns that may be artificially inflating publishers’ earnings and advertisers’ costs.

    The two issues are closely related with “Invalid traffic concerns” being the more severe of the two. Both will result in a large proportion of AdSense/AdMob impressions remaining unfilled by Google, which can have a very severe impact on revenue.

    Why does Google limit ad serving?

    Ad Serving limits are used by Google to limit the impact of invalid traffic whilst they investigate a potential issue with some inventory. Similar to the dreaded Click-confirmation behavior (AKA the two-click penalty), it is a tactic that allows them to protect advertisers from a potential issue whilst determining whether there really is an issue to be concerned about. Whilst ad serving is limited, the AdSense tags will still be called, allowing Google to analyse every request. Fewer of those requests will result in filled impressions (ads on page), which means significantly lower revenue.

    This seems to be an automated process in most cases. This “investigation” likely isn’t Google manually looking at your account performance, but simply your traffic getting greater attention and scrutinyt from Google’s automated systems.

    Limiting ad serving is just one of the tools that Google uses to combat Invalid Traffic on its network. Invalid Traffic (or IVT) is a catch-all term for traffic in the ad ecosystem that does not result from genuine human interest. It includes bots, accidental clicks, click-fraud, and incentivized traffic. Advertisers get no value from this traffic and reduce spend where it appears, so reducing IVT is in everyone’s long-term interest – even if the methods used can be very painful in the short term. You can learn more about identifying and preventing Invalid Traffic and Invalid Activity here.

    Ad serving limits are actually a good thing

    This might be difficult to believe if your earnings are on the floor because of ad-serving limits, but these limits are better than the alternatives.  In the past concerns over traffic quality would be met with swift account terminations. The web is still littered with reports from publishers upset at this summary treatment. Ad serving limits are a difficult pill, but they do at least provide a way for Google to maintain traffic quality (and keep buyer confidence) without permanently terminating accounts. If you are currently experiencing drastically reduced earnings due to ad serving limits you can at least be slightly reassured that if you are doing nothing wrong, then it should be temporary and fixable.

    Can social media promotion result in limited ad serving?

    Having spoken to a lot of publishers affected by ad serving limits, the idea that it happened “because I posted on Facebook/Instagram/Twitter/TikTok” comes up a lot. There are definitely times when traffic spikes from social media promotion triggers ad serving limits, but the cause seems more commonly to be the message than the media. Social media can be a powerful way to drive traffic to your website. There is nothing wrong with doing that, (and at OKO we work very successfully with plenty of websites that have a high proportion of social media traffic), but there are certain AdSense policies that can be easy to break on social media if you are not careful.

    The AdSense policy around incentivised traffic is one that frequently causes issues with social media promotions. Calls to action like “Click for a chance to win” or “Visit my website for a discount” can be very effective at driving traffic, but would definitely count as incentivising clicks. It is my belief that Google looks at the calls to action being used when they detect spikes of non-organic traffic. Publishers seeing AdSense serving limits after recent spikes of social media traffic are advised to look closely at the posts that drove these traffic spikes and make sure that there is nothing that looks like incentivised traffic before those posts get reviewed.

    Does limited ad serving affect Ad Exchange as well as AdSense?

    At time of writing, we are only aware of ad serving being limited in this way with AdSense, not with Google’s premium monetisation solution Ad Exchange. This might be that the system has simply not been added to Ad Exchange yet, but it is equally likely that it will never be seen on Ad Exchange accounts. There are many many more AdSense accounts than there are accounts on the Google Ad Exchange. This means that AdSense tends to utilise more automated and machine learning systems so that they are able to provide support at the scale AdSense requires. Publishers with an Ad Exchange account are more likely to receive a call from their Google rep if there are traffic quality concerns, whereas AdSense relies more on automated processes for quality control.

    What to do if your AdSense ads serving is limited

    Once hit with limited ad serving, most publishers just wait for the limit to be lifted. The vast majority of cases seem to resolve on their own within 2-4 weeks without any additional steps being taken by the publisher. That can be an expensive wait and Google is unlikely to start fully serving again until they are satisfied that there are no issues, so we advise being proactive and taking action to try and minimise that timeframe, ensure a good outcome and reduce the likelihood of limits being placed in the future.

    Steps to take:

    1. Check your account for clues: What does the ad restriction warning say? Carefully consider the exact wording used – there are various notices that can appear and these do provide clues as to the cause for concern. Check the AdSense Policy Centre whilst you are there. Invalid activity includes ads served outside policy. Are there issues that have appeared before that could now be triggering the problem? The AdSense Policy Centre can include plenty of clues as to where Google has an issue with your ad serving. Work through the points flagged and work to fix them accordingly.
    2. Consider recent on-site changes: Have any ad units moved? Are there any layout changes that might have introduced issues?
    3. Check your traffic sources: Are you confident that you do not have significant traffic that is not from humans with a genuine interest in your  content? If not, then turn off or block any potentially problematic sources. Pay particular attention to any traffic sources that have increased in volume prior to the warning appearing.
    4. Check ad placements: Accidental clicks are a common source of invalid traffic. Verify that that you have sufficient space between ads and other clickable elements across all common device types. Check to ensure that navigation doesn’t cover ads and that the placements aren’t going to encourage clicks (such as lining up with images or near “Next” buttons). Consider whether the way you insert ads might be causing problematic placements (this includes “Auto-ads” as well as ad insertion plugins). When in doubt, add space.
    5. Checks ads and CTAs: If your traffic comes from sources other than organic search, take an objective look at whether there is anything about that traffic that would potentially concern advertisers. Again, the yard stick should be “humans with a genuine interest in your  content”.

    Should I delete all my ad units and recreate them?

    There is a lot of advice online that publishers delete all their AdSense ad units from account, remove code from the website and wait a couple of weeks before recreating the units. Some even suggest deleting ads.txt entries and deauthorising domains. The theory is that this will cause the issue to be cleared more quickly.

    It is difficult to support this advice with confidence. The timescales for the issue clearing for publishers who have taken this approach don’t seem to be very different from those who have just waited it out. There is also a risk that by deleting the AdSense code you are removing Google’s ability to analyse the traffic and determine that all is well. New ad units also tend to perform worse than established ones after an initial “new unit boost”, which could have longer term implications.

    Until we see more compelling evidence for the “delete and wait” approach, my advice would be to look for issues first. If you are able to find and fix issues that you believe may have contributed to the problem then leave your code and ads.txt in place so that Google is able to see those improvements.

    Someone has offered to fix the problem. Should I let them?

    We are being made increasingly aware of publishers who discuss the option openly being approached by people or parties claiming that they can fix it for them. These people generally promise quick results without convincing explanations of how they will remedy the problem. As part of the process, they will usually request access to sensitive systems like the publisher’s AdSense account, Ad Manager, Search Console and/or website login or payment up front.

    We would always urge extreme caution when sharing such access. Many scams that target publishers start with the same requests. Our advice would be not to share such access with individuals and companies that you don’t already have an established relationship with, unless they have been vetted as part of the Google Certified Publisher Program (GCPP).

    How can publishers prevent ad serving from being limited?

    As publishers, it is our responsibility to ensure the quality of the traffic we send to our ad partners. This not only keeps our accounts in good standing but helps ensure strong bids and good long-term revenue. In practice, that can be difficult. Publishers don’t have the same visibility on traffic quality that partners like Google do. There are steps we can take prevent traffic quality issues though:

    Play fair

    The vast majority of publishers are not out to trick advertisers out of money, and those that are will be unlikely to read this guide. However, it can sometimes be difficult to make changes that carry a short term cost impact. Publishers will often spot an ad unit that has an unexpectedly high CTR, for instance, and be slow to implement a fix that costs them money. This inaction can be costly if advertisers start reducing bids, ad serving gets limited or in the worst case scenario accounts get suspended.

    Being mindful of providing ad inventory that delivers value for publishers is a good way to promote long term success. After all, the highest-earning publishers didn’t get there by tricking their users into accidentally clicking ads.

    Seek out strange patterns

    Most AdSense publishers will be familiar with the CTR of their main ad units, but when did you last look at the relative click-through rate of a unit by Geo? Or Browser, or time of day? IVT isn’t always indicated by high CTR, but unusual CTR patterns can certainly be an indicator of an issue.

    Periodically checking for these patterns can be a useful way of identifying issues early and and zeroing in on problems before they occur. However, the same techniques can be crucial if you are trying to solve an issue with ad serving being limited.

    The good news is that you already have the tools to do this. AdSense reporting provides incredible granularity and enables publishers to slice and dice the data in all sorts of interesting ways.

    Reports – Google Adsense

    For example, this ad unit has an overall CTR of just 0.77%, but users in Norway are 45X more likely to click the same unit.

    If you have your Google Analytics account linked to AdSense then you have even more options. Analyzing performance by device or traffic source can turn up equally interesting results. Be warned though – if someone was deliberately targeting your website with invalid traffic, they may block the Analytics script from running.

    Block bad traffic

    If you identify bad traffic patterns, the best course of action is not to serve ads to that traffic. If you use an ad server, like Google Ad Manager, this can be done by adjusting your traffic. If you use “tags on page” (which most AdSense publishers do), then you can wrap those tags in some additional server logic to ensure that the page serves, but without ads, to the suspect segments of your audience. A simpler approach is often just to block that traffic completely, either by adding some access rules to your htaccess file or using a firewall.

    Consider a service like Cloudflare if you aren’t using it, and reconfigure it if you are

    We’re big fans of Cloudflare here at OKO. Many publishers are already using Cloudflare in its primary role as a CDN/Optimisation service that speeds up their website for their users. Cloudflare is great for that, but it can also be a big help in the fight against invalid traffic.

    Firewall rules: At the time of writing, firewall rules are only available in the Pro level of Cloudflare and above, but these features easily justifies the $20/month subscription cost on their own. Using Firewall rules, you can easily put rules in place to block or challenge traffic that matches your suspect segments.

    Bot fight mode: A less known, but excellent option is Cloudflare’s bot fight mode. This is a largely hands-off setting that is available even to domains on the free level of Cloudflare. Once enabled, Cloudflare will automatically look for signs of bot behavior and intercept that traffic. We’ve seen good results with this with information-rich sites that are often the targets of “unsophisticated invalid traffic” like scrapers.

    Firewall Buzzbox Io Account Cloudflare Web Performance Security

    Bot fight mode is easy to enable for publishers using Cloudflare who are targeted by unsophisticated bots.

    Watch your ad spacing

    One of the most common causes of accidental clicks is poor spacing between ad units and active elements, such as navigation and buttons. This is particularly a problem on mobile, where the accuracy of a finger is so much poorer than a mouse pointer. Accidental clicks result in publishers paying for low-quality traffic as advertisers will reduce bids. Common examples of this are navigation that expands over ads and ad units close to buttons and navigation.

    Don’t allow ads to be confused as content

    Another common cause of accidental clicks is when ads are formatted to look like content. If users click an ad that they believe is content, they are very likely to click back or close when they end up on an unexpected site. This will be a clear sign of an unintended click to Google. This is another situation where publishers are sometimes reluctant to implement changes that reduce their short term revenue, but such issues can cause serious account level problems.

    Be careful when buying traffic

    There is a lot of confusion around AdSense and AdX and paid traffic, but it really is quite simple: There is nothing wrong with buying traffic for your site, but that traffic has to be genuine.

    Genuine traffic doesn’t just mean human users, either. Those users have to be visiting your site with genuine intent. Cheaper traffic will often come from users who are tricked into visiting (pop-unders, toolbars, redirects, etc.) or incentivized to do so (pay-to-browse programs, etc), both can be huge problems.

    Other things to beware of are those companies who are effectively traffic resellers, buying their traffic from one site and selling it to another. Because there is a strong incentive for the originating source to send low-quality traffic, that will pass through the system and end up impacting your account. Content recommendation services can be prone to this. Even the best-known ones as they run vast networks and don’t have a great incentive to enforce traffic quality.

    Traffic bought directly from top-tier sources like Google Ads, Facebook, and well-known content sites is generally safe, but it can be a good idea to introduce additional traffic quality systems if you are buying from other sources.

    Can’t be bothered with all of this?

    It’s no secret that ad serving has been getting more complicated in recent years. Invalid traffic is just the latest in a series of challenges publishers have had to deal with. With no end to the complexity in site, a growing number of publishers choose to partner with a Certified Publishing Partner like OKO. Working with OKO means partnering with an expert who can guide you through these complexities and even steer you away from them before they affect you. Get in touch today to find out how we can help you.

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