From recent buzz and confirmation from two trusted sources, it sounds like Yahoo closed its rumored acquisition of Joe Kraus’ Jotspot, and will be entering the wiki market. No official announcement of this, or any indication of price (buy Yahoo is famously stingy).
I’m putting this rumor at 85% likely, partially because Yahoo has a pre-existing business relationship with PBWiki to create wikis for Yahoo Groups. More as this develops. Our previous posts on JotSpot and its products are at this link.