My Web 2.0 favorite apps

One thing I like to do is test Web 2.0 applications. Ajaxian is in my favorite feeds. But there are three applications that change my habits in the Web.

• Delicious. All that things that could be interesting I save in delicious. And my network is one of best source of really interesting things.
• Google Reader. Previously I used to read my feeds in Thunderbird at home and work, and I had to mark as a read many many feeds in both sites. Google Reader it's very useful with two clicks on firefox I have a new feed, and I share my starred items.
• Last.fm. Usually, I listen many music at work, and last.fm help me to find new groups, and share with my friends. My profile tells me who are my favorite groups now. The Killers and Coldplay, are winning.