an even larger change from Wiki meaning fast to Wiki meaning, as you say, a kind of web application.

Yes, though, the reason they called it wiki, besides the alliteration with web was because of the quick-turn-around in letting everybody edit the web pages; and, Cunningham saw Wiki wiki on the sides of shuttle buses at the Honolulu Airport. So that meaning is interposed between fast and the kind of web application.

Ceci n'est pas un seing.