Google’s Gary Illyes said on the last Search Off the Record podcast that Google can crawl certain sections of your site more frequently and also infer the quality of certain sections of your site differently.

This came up at the 9:09 minute mark into the podcast but Glenn Gabe summarized it super well on Twitter. Glenn said “Google can infer from a site overall which areas they might need to crawl more frequently. E.g. if there’s a blog subdirectory & there are signals that it’s popular/important, then Google might want to crawl there more.” ” And it’s not just update frequency, it’s also about quality. E.g. if G sees a certain pattern is popular (folder), & people are talking about it & linking to it, then it’s a signal that ppl like that directory,” he added.

Here is the video embed:

Here is the transcript of this section on crawl frequency by section of the site:

Then here is the section on quality:

Forum discussion at Twitter.