I love Tumblr. It's incredibly easy to use and is definitely more about self-expression than communication, unlike a lot of other blog servers. There's no commenting or anything along those lines, which is actually kind of refreshing.
Giving Tumblr a go, now, using it as a sort of supplement to Girl Meets NYC...one I can easily update more then every 2 weeks or so, unlike Girl Meets NYC. I like composing entries for GMNYC, but it's time cosuming, especially replying to all the comments, (which I love and appreciate, don't get me wrong, but it does take me like 5 hours per every 100 comments, in replying) and the fun thing about Tumblr, is I can crank out entries quickly, and just share little bits here and there. I like the format and simplicity of it all.