I'd say super-active discussions started dropping after 2013 or so. I do recall 2014 being the point I noticed activity on VocaloidOtaku started to decrease, away from shitposts towards more thoughtful conversations - not necessarily a bad thing, but it did reflect the trends I've already mentioned with social media. VO's death in 2018 directly led to the creation of VV, because some of us on VO wanted to carry on with forum-based discussions without the baggage VO had gained over the years.I thought the VVN or vocal synth community has been like this since long time ago?
i hate social media. sighVV always goes a bit dead when no big news is announced for a while. Also, forums are nowhere near as popular as they used to be, at least compared to 20 years ago. Even 15 years ago, VocaloidOtaku used to be really active; then social media platforms like Tumblr, Reddit and Instagram started stealing the users who would have hung out on forums otherwise.