History of KiSS
Over the decade or so when KiSS was actively used, different groups of people used KiSS in different ways. I'm basing the dates below on OtakuWorld's "time" listing and vague memory, since I wasn't around for most of it. Would appreciate clarification from long-time participants in the community.
I just feel sure that there were broadly two eras of KiSS: an earlier, male-dominated era (corresponding to the male-dominated internet in general) and a later, female-dominated era (when teenage girls started using the internet/the era of dollz). Here's an essay about early (pre-FKiSS) culture: it doesn't speak to my experiences as a KiSS doll player or artist AT ALL. For us, our dolls were all about dressing UP, not the hypersexualized stripping of earlier dolls. There's no clear-cut time when this shift happened, but there definitely was a shift.
Most dolls were based on anime/manga characters. Dolls had small wardrobes and no animations/effects (FKiSS didn't exist yet).
An early Sailor Moon doll by MIO.
Most dolls are still based on anime, but now non-Japanese artists are making them. They're also making original character and comic book-inspired dolls.
Male and Female Ranma by Dov Sherman
I feel like there was an "era" here, when KiSS wasn't all about anime and it wasn't all about cute fashion either. Maybe call it the "era of Emby Quinn". :)
Emby Quinn self portrait
This is the era I'm most familiar with. Kimiki, Silent Angel, Punky, and RyogasGirl all started making dolls in 1999-2000. All four were teenage girls and anime fans and together they started the trend of cute fashion dolls that took over the community at its peak popularity. Their dolls were mostly very kid-friendly and attracted a lot of younger people to KiSS.
By 2008, the KiSS dolls forums were dead, the few artists left had moved to deviantART, and only a few dolls were being uploaded to the Big KiSS Page each month. The Big KiSS Page was last updated in 2012. So what killed KiSS?
The most important factor (IMHO) is that tools and viewers and the tutorials dependent on them became out of date. In the mid 2000's, artists who upgraded their operating systems started finding that their KiSS-making tools were broken. The work-arounds and alternatives were so frustrating they'd often quit making dolls altogether. Aspiring new artists had to figure out which tutorials were accurate and which were outdated, so usually they quit and went to other technologies like IMVU or Flash. Today UltraKiSS is the only one remaining, and I'm not sure the last time it was updated.
The KiSS community was also far too dependent on a single site, OtakuWorld, and a single developer, Dov. Dov did incredible work, but KiSS artists should've taken more onto themselves in terms of hosting dolls and creating tools. When Dov was unable to update the Big KiSS Page (for over a year?) at one point, it was pretty much the death knell for the community.