I feel obligated to try and answer this, because I've been around this scene online for about 25 years, but at the same time I don't feel like I have a very wide view, so I don't know if my take is reflective of what others have experienced. Anyway, here is just some "this is what I remember from way back when", all just based on memory with no research to double check exact dates or order that things occurred in.
So in the beginning there was darkness ... or at least, while there may have been plenty of people with desires to gain weight of for a fat and gaining partner, there wasn't even vocabulary for that, forget about places to talk about it But some people were looking for that, of course. There were a few physical magazines that had explored this space in one way or another, for some length of time or another, and then the world wide web became a thing. I didn't get online until early 1996 (16k dial-up modem!). Having stumbled across a couple of back-issues of BUF magazine some years previous I at least knew the terms BBW, FA, and feeder and feedee. There was no google search at the time and the available search engines were pretty bad, and combined with the slow access speed it could take a long time to find anything. But I was home sick one day so had time and went looking. I found a grand total of three sites with any content to speak of that were remotely related:
- Dimensions Magazine online, the web site for the print magazine. There was little here at the time (maybe the wannabes photos? I don't remember)
- The site of one FA/feedist, a young woman named Melanie Bell, who had a few gaining stories as well as maintaining an apparently lightly fictionalized diary. This was the most openly feedist material on the web at the time
- A site called BBWQT that was an effort to create something like a BBW/FA dating site, allowing women to post a picture or two and a personal ad, and there was some way for guys to reach out to them. A lot of the women had comments like "No feeders!" but a couple seemed more open to it
And that was about it, for several months. Worse, Melanie Bell came clean about her fetish with her partner, apparently resulting in a fight and maybe break-up, and her site basically went silent without any real activity after that. But then in early 1997 (IIRC) the BBWQT site added a discussion board, and not longer after a chat room! Both were soon aflame over the topic of whether feeders should be allowed in or not, and she responded by splitting both in two, creating 'The Weight Board' and 'The Weight Room' if I remember the names properly. There was still enough anti-feedist sentiment around that when I first posted on The Weight Board I did it under a different user name, not wanting to ruin my reputation on the original board.
At the time it was still very heavily slanted towards fat women and male admirers. One of my first posts on The Weight Board was a story that was mostly about male gain (there was some female gain too, but it was driven more by the guys gain), and the only response I got was roughly "We don't want any of that male gainer crap on here."
The web boards and the chat room rapidly became pretty popular, to the extent that the bandwidth costs were becoming significant, and more that the lady who had created them could support. Somehow a deal was struck, and they migrated to the Dimensions Magazine website, and she stayed on as web master. After that a number of new chat rooms and new boards were added over time, although when it came to the chat rooms it was always mostly one 'genera' chat and one 'feeder' chat going on with the other rooms being empty.
An ongoing issue was that there tended to be more men active in the Weight Board and in the feeder chats, and more women in the general areas, and also that the weight gain/feedist activity was often a bit spicier. This would result in more people moving over from the general to the feedist spaces, seeking activity, attention, or titillation, but their presence would also bring in more non-feedists, and a general air of disapproval about more overt feedist content. This led the feedists to migrate between the various chat rooms a number of times, and eventually many left the Dimensions chat rooms to the chat room created by Kelligrl.
Kelligrl was an infamous figure online, the first person most of us knew who was explicitly trying to make money by offering weight gain porn. She created her own site, I know there was some way you could pay for more access, but she also made a free chat room, and that was the home of feedist chat for a year or so I'd say. (eventually she would shut down her site with no explanation).
Sometime around then other sites started springing up, I don't remember what all and when, but Dimensions stopped being 'the place' for all things bbw/FA/feedist, but there was still a lot going on here (it became a bit more 'social media' before we used that term, with less focus on dating and FA erotica). A lot of the other sites seemed to come and go a lot, started with enthusiasm but not getting much traction and shutting down or at least fading away.
The BHM/FFA board was started on Dimensions, which started off slowly but gradually did prove that there were real, live, FFA out in the wild, and I think that helped broaden the community to be more generally 'fat people and their admirers, and gainers and their encouragers' sort of view, instead of being so heavily gendered (the entire scene still slants gendered, but it is no longer as blatant about it)
More later, this is plenty long enough for now.