For several of my interests I still participate in the modern version of what would previously have been dedicated websites powered by forums, but they are now on Facebook / reddit / discord and collections of YT videos. The quality of information is nowhere near what it was. The amount of spam, platform ads, and useless posts to drive engagement is easily over 50% of the content. There is no timely cohesive flow of posts or discussion. The benefits are far more members and consistent mobile access but they come with huge tradeoffs. Prioritizing mobile has many downsides and most of those users do not meaningfully contribute or even actively pollute the content.
It's not just nostalgia, the quality of content and sense of community was much better when people went into their own corners to discuss things vs everyone standing in the center and yelling over the background noise of a common ad-suoported platform.