One of things that makes Tumblr so addictive is its ease of use. The Tumblr bookmarklet is magical. It’s too easy to grab a photo, quote or link and then post on your tumblelog.
Many folks start using Tumblr by ingesting their various personal feeds (flickr, twitter, etc) to get going. Then when they start using the bookmarklet their tumblelog’s become amazing.
The thing that was less obvious to me initially is the Tumblr notion of ReBlogging. But now I totally get it. And I love ReBlogging. It’s a simple way of sharing content you discover on other tumblelogs and add commentary.
Give it a try.