Some of the stranger behaviors of anime fans can make people cringe, like sleeping with a body pillow designed after a character in a show. Shows themselves make people cringe with inappropriate relationships, worn-out cliches, and excessive fan service. Ridiculous arguments among fans are also cringey.
Overall, the best platform is probably MyAnimeList. It’s designed specifically for sharing information related to anime, and pretty much all anime fans use it. From there, Twitter is the best for official announcements, and Facebook is the best for finding local groups and making in-person connections.