A service I can't imagine a good use for except as an art project.

[theweaselking]

WhoIsLive: a browser plugin that adds a chat room to all websites. The members of the chatroom? All other WhoIsLive users currently looking at that page.

Comments

[lederhosen.livejournal.com]

I can see it being useful occasionally. The ability to chat with anybody else looking at the online "Dark Dungeons" might be entertaining... but not seeing a lot of demand for it, no.