User blog comment:MisterWoodhouse/Social Activity, the 2010 Editor, and Unpausing Migrations/@comment-24937036-20201014135240/@comment-1038387-20201015202211

First, that's been said without source references, so questionable, could even be vastly outdated.

Well, it's one of the reasons. It seemd like a good idea at the time, but the way the pagination is set up, Google counts all the pages as duplicates. Having duplicate pages (or ~80% the shared content pages) on your wiki causes Google to discard it as a non-page; the larger percentage of your total page count is a non-page, the bigger the punishment in SEO Google gives. Dynamic Categories were created specifically to fix the SEO problems of both Classic and Exhibition.