I’m not a fan of Tumblr. At the moment I use it for a partial life stream (a chronological aggregated view of your life activities both online and offline – thanks Krynsky). It is just publishing a feed of several of my blogs. It a very limited public view.
The one main thing I dislike about Tumblr is the lack of comments. While my blog doesn’t have a lot of comments, I like that it offers the opportunity. Tumblr not having the opportunity means publishing in a vacuum. Which I think defeats the purpose. So I’d never use Tumblr to replace this or any other blog unless comments appear or comments become less important to me.
A confusing aspect of their service is the “Re-blog”. It wasn’t clear to me for some time items re-blogged were not created by the person doing so. Unlike most other services making life streams, there is not an indicator an item did not originate from another site other than in many cases they are abbreviated and have a link to the source.
I probably will continue to use it for some time to come. It just is not something I use. Stuff just flows there from the places I do use.