fav.or.it is our answer to the current separation of feed reading and commenting. We have built a web interface that lets you read all your favorite content and at the same time take part in an interactive community.
To make a simple analogy: If blogs are journals, tumblelogs are scrapbooks. You can also look at tumblelogs as slightly more structured blogs that make it easier, faster, and more fun to post and share stuff you find or create.