Writely. I just got admitted to Writely. I applied quite awhile ago, after reading about it in the Wall Street Journal. I will be exploring its uses and how I can link larger documents to my blog. I don't recall reading about it on Sean's blog. (Sean, did I scoop you on this?? Could that be possible??)
UPDATE: Nooop, not possible. Sean blogged on this in April. I did search his blog for "Writely" before saying such an audacious thing, but the search feature didn't work. Nor did the link I tried to copy over here. But he's into Writely.