I was knee-deep in the flash animation scene through the late 90s early 00s, and I don't remember anyone calling anyone 'Flashers'. China-only I suppose.
I did think Stick Death came out before Xiao Xiao?
There’s not much in the group gallery now, so probably I was looking in the individual galleries of some of the members and I think some of the time some member would make something and post it to Albino Blacksheep and sites like that and maybe post a journal entry about it to their own individual journal on their own profile.
deviantArt also had IRC-like group chats. Flashers had a chat room. There’s a link to it still in the about section of the group, but that link doesn’t work any more. Even if a group didn’t have much posted into its gallery they could have a lot of member activity in those chat rooms. And from what I remember, I think I visited the flashers chat room a few times and that it was pretty active.
I think some chat rooms were private, and some were open even to people who were not in any particular group.
I did think Stick Death came out before Xiao Xiao?