If we talk about the more technical/gear side of things, not focused on noise, there are still very interesting forums with lively discussions and depth of knowledge not found on social media. Some are great for discussion, some are good for information only but that's okay too. If we talk about the youth or people below 30 or 40, most of the discussions have been moved to 'the socials'. Certainly is a shame!
If we talk about pure music forums, I think only a few are left alive. Grimeforums is dead. IHATEBREAKCORE is dead. even most general Dutch music forums are dead. However DogsOnAcid is still living somehow.