JogTheWeb - webpage slideshow, also see webslides and TrailFire.
BoostCast - create your own video sharing site, also see Digital Reality.
YouFig - a whitelabel community…there are so many of these sites now, Ning still does it for me.
Posterous - microblogging like Tumblr, mambler and Soup.io
Protonotes - annotate a website with stickynotes, as if there aren’t enough of these, but it does look nifty and collaborative