For those of you who don't visit my website and only read it via RSS, I've now added a perhaps voyeristic feature to my site: a status message from twitter. Twitter is an SMS-based service where you can update a group of people with a single text message or a short message from the web. The message is then sent to your buddies over SMS and is available to be queried over the web. People can "subscribe" your presence and you can "subscribe" to other people's presence. You receive the updates over SMS.
I'm sure the carriers absolutely love Twitter because it drives the use of text messaging. Too bad more people I know don't use it.