Digging around in Ye Olde Plural Sites, figured I'd toss some stuff up here before I forget it all.
I found
the Vickis' old site from ~1998. As far as I understand right now, they may have propagated the term "midcontinuum," before "median" was in use. (And it turns out that "median" was apparently associated with Pavilion Hall, a multi "activist" group that was a rolling trash fire and had their own bizarro quasi-metaphysical explanation for what being in-between multi and singlet was. It made no fucking sense.) The Vickis might also have helped
start the idea of "plural" as an umbrella term, more expansive than "multiple," a term they were using by 1/15/1998. I'll probably have to dig through the alt.support.dissociation archives to test this for sure.
Their site has some really good stuff on it! I especially want to bring attention to the following three essays:
Does it work? -- An essay that tackles the question of "I am multiple?" and fears of faking better than anything else I've seen.
The Power of Naming -- Who gets to decide what a "real" multiple is, and why?
Building Safety and Trust -- a post by BigVicki (and a couple of other ASDers) on how to build safety, trust, and communication within your system/household, especially if you've gotten off on the wrong foot.
All of these essays are highly relevant to plurals today, twenty years later, and the Vickis are one of the few systems I see talking about the in-between spaces, which I feel is much-needed. I have no idea if they're around anymore, or how to contact them, so I can't get their permission, but I plan to have these linked on the healthymultiplicity.com home page, since I feel their utility can't be denied and mustn't be lost.