If you search about Bitcoin and find forum for Bitcoin discussions, I am sure with you a first search result would be Bitcointalk.org because it is a biggest forum for Bitcoin talk/ discussions.

Cryptotalk is a forum which was advertised on Bitcointalk years ago in 2018 or 2019 with support from Yobit team. That campaign initially was managed by Yobit team and caused massive spam on the forum. Later, Yobit account was banned here and Yobit (Cryptotalk) participants were banned a few weeks or months too (the more report against their spam posts, longer ban time). Later Cryptotalk campaign was managed by yahoo62278.

Long story, short note, by their campaign here, you can easily see what is a bigger forum between Bitcointalk and Cryptotalk.

List of banned participants in the Cryptotalk Campaign