I seem to be a verb

On good days, my Soup is (or rather: my Soups are) a much better representation of myself than, say, a Facebook or Xing profile can ever be. It's not a collection of facts about me or a showing-off of social contacts, it's a fairly accurate account of what I spend time on, the topics that fascinate me, what I'm reading and thinking – or at least the subset of that I am willing and motivated to share. On Soup, my public identity is defined not by which education I received or who I know, but by something that appears more meaningful to me, while still requiring a lot less effort than keeping a journal: A low-friction stream of multimedia content, mixing things I created myself with things I found elsewhere and appreciated.

I keep this Soup to share all that stuff with friends to allow ambient intimacy, with people who don't know me yet to provoke serendipitous new contacts, for myself to build an archive I can later look back upon – and to a large extent just to indulge in the joy of creation.

That's what tumblelogging means to me, personally.
Other people use tumblelogs for quite different purposes: Collecting funny pictures from the internet, aggregating some personal feeds, gathering tidbits about a specific topic, publically documenting a relationship or a trip, keeping a mini-diary, and so on.
All of those are great, and attest to the wide appeal and the enormous growth potential of the concept of easy, no-overhead publishing.

Why do you tumblelog?