Google AdSense are being their usual mysterious selves and don’t share what the specific requirements are to be approved for their Matched content recommendation units anywhere in their official help documents. However, the exact requirements have actually been revealed in a comment from an AdSense support representative.
Matched content is an AdSense feature that will show contextually relevant and recommended articles at the bottom of your web pages. The feature is meant to increase how much time your readers spend on your website as they’ll be presented with more [hopefully] interesting content to read when they’re done with reading one story.
The feature isn’t available to every AdSense publisher, however.
Reading statements like this can be more than a little frustrating if your website hasn’t been approved to use the now matched content recommendation units with your AdSense account. Some good concrete numbers are much more appreciated than vague generalizations with no frame of reference.
Luckily, AdSense staff aren’t as silent as AdSense’s documentation department, or maybe they’re not as good at keeping secrets. Whatever the case, they’ve let slip the specific requirements (as the only valuable piece of information to come out from a) a Q&A session :
This answer can be hard to discover as Google seem to be having technical difficulties with indexing comments on Google+. Or maybe they’ve deemed them of so little value that they’re not worth indexing? Whatever the case, it took some digging to find this.
The same numbers where later reposted verbatim by a Google AdSense employee as late as on Quora.
I’d take these number with a grain of salt, however. E.g. this blog is eligible for matched content recommendations units with and without ads. But it doesn’t have over a thousand articles, only around 300. This blog does have a whole lot of readers visiting every day, though — so the numbers may not be all that accurate nor a strict requirement after all.
I also suspect that your AdSense account’s historic revenue performance will play a role in whether or not your websites is eligible for Matched content recommendations. I’d also hazard to guess that Google search’s secret recipe for what makes for high quality content could also have an effect on a publisher’s eligibility.
Although AdSense Matched content’s recommendations aren’t all that bad within a service category with a really bad track record, I’ve opted to only show them to a small fraction of my readers.
The majority of readers will instead see recommendations from a system I wrote myself. As I’ve been able to tune this system for the content that are actually on my site, it has proven very effective with higher click-through rates than anything I get with a third-party service like Matched content by AdSense.