Jaiku.com might resemble Twitter but it's much more interesting. Apart from allowing you to publish your status (e.g. "Right now I am picking my nose and eating the snot.") using web interface, IM or SMS, it also also displays feeds from whatever sources you define. That means you can have one cleanly organized stream of your personal thoughts and all your public activities.
When you look at fuxoft.jaiku.com, you can see my status changes ("wha I am doing right now" - like on Twitter), but - more importantly - you can see my blogposts, my photos uploaded to Flickr, my videos favorited at YouTube and interesting links I found using Google Reader sharing. Everything on a single page with automatically generated RSS feed. If you want to know about "everything Fuxoft is up to", this is the page to go to (or subscribe to).
In order to prevent flooding of person's Jaiku stream with dozens of items each day, the items from each source are indexed only once every 24 hours. You have to click on "... and XY more" link in each post to see special page where all the items from this day and from this feed are displayed (in the right-hand column).
Jaiku has been bought by Google and you can probably expect its integration into Google infrastructure fairly soon.
Jaiku registrations are not yet public but everyone has been given an infinite number of invites recently. If you want to register at jaiku, I can send you the invite. But if you just want to watch what I'm up to, you don't have to register at all!