While I’m still not convinced about Twitter, I think that TwitThis could be a step towards the Twitter killer app. Pete Cashmore at Mashable! thinks it has legs, but that the critical mass amongst mainstream users rather than geeks is more likely to make it:
the next Flickr (a huge site by any means), but not the next YouTube or MySpace (world changing)
With browser buttons, direct integration on web pages and a WordPress plugin as options, TwitThis allows you to immediately send a page to your Twitter account. TwitThis also has a good-sized list of verbs associated with the send action, such as “Listening to”, “Laughing at”, “Responding to”, “Waiting for”, “Looking forward to”, etc. These are the things that strike me as most useful. While I don’t care to know that my Twitter pals are heading off to lunch, I do want to know they’ve seen a useful page, or are interested in something I may also be interested in.