A link is to a blog post if and only if a) the linked-to page contains a feed autodiscovery tag and b) the autodiscovered feed contains an entry for the same pa

A link is to a blog post if and only if a) the linked-to page contains a feed autodiscovery tag and b) the autodiscovered feed contains an entry for the same page and c) that feed entry is at least half as long as the page (in words). That test isn't quite right. The false negatives include links to old blog posts, and the false positives include the honourable few sites that provide full-textish feeds of something other than a blog. But it's pretty good if you want to filter away content marketing and read tech blogs.