My own experiences with bulletin boards have been in the realm of jazz (Jazz Central Station, Jazz Corner) and food (Chowhound). The online bulletin board, or BBS, pretty much got rolling after the advent of the web browser and picked up on a phenomenon that began with newsgroups on the much less wieldy Usenet. So, for instance, where there was once lots of activity on the rec.music.bluenote group (peak usage was in 1995), jazz bulletin boards that sprung up around that time or shortly thereafter, such as Jazz Online and Jazz Central Station, both now long defunct, took over much of the traffic. By the late '90s into the mid-2000s there was plenty of activity on the bulletin boards by a mix of highly knowledgeable fans and professionals as well as curious novices. For a time one could always expect spirited discussions on a range of musical topics. And they were open forums. All you had to do was register, and you could become a member of a virtual, shared-interest community. Sure there were the usual online issues of trolls, bullies and cliques, but that's what you get in an open forum.
By the mid-2000s, however, a confluence of changing paradigms and generational assumptions and preferences led to a waning of the public bulletin board in favor of the self-selected cells of social media like Facebook. Less drama (generally) perhaps, but also less chance for the surprise contribution from a particularly knowledgeable individual you've never heard from before. On Facebook I have friends from a number of corners of my life: close friends, literary acquaintances, music world acquaintances. But on a jazz bulletin board there was always a critical mass of people with one particular shared interest. I could throw out a question or rehearse a hunch and count on some interesting responses and discussion. For me this was one of the great promises of the internet, bringing together like-minded people who might not otherwise know each other for lively discussion of a shared interest. I even posited, while working on a degree in Library Science, that the BBS could be a great reference resource, as one had access to what I called a community of "experts without portfolio." And a side benefit was striking up real-world, lasting friendships with some of my cyber pals, people I met when they came to New York or when I went to a music festival overseas.
The BBS for me was one of the mechanisms that helped to foster the democratic promise of the internet. I don't think the more atomized landscape of social media has nearly the same power.