A really good place to get caught up on the latest in Web apps is the netcast Net@Nite from Leo Laport and Twit. Here’s their website:
or you can just subscribe to the podcast from iTunes.
Anyway, episode 21 talked about Tumblr
It’s kind of a combination blog and scrapbook. You can add things to it really easily but there’re no comments allowed. It’s just the thing to keep stuff that you find on your wanderings around the Net.