The folks at Eqo, previously known for their attempts to bring Skype to your mobile phone, are bringing social networking to your mobile phone. A "flash widget" (shown above, if you're reading from the website) shows people whether or not you're online, where you are, and what you're doing. People can leave you messages on the website and they are forwarded to your mobile phone. If you are in the US, you can receive SMS notification of new messages. You can also update your status from a mobile using a normal phone browser and/or check your messages as appropriate.
The requirement for data services on the phone might also be a mistake, or at least limits their potential market unnecessarily. At least in the US (and probably Canada as well), data services on the phone aren't cheap. SMS is cheap, plentiful, and more people use it than data services. MMS isn't a whle lot harder to use than SMS. There's no reason they couldn't allow for updates via SMS or MMS, the latter of which would allow photo uploads. Furthermore, there's no reason they couldn't do updates to the phone via SMS (or at the very least, to an arbitrary email address).
Anyway, this will be an interesting product to follow. I'll put the badge in this article as well as my "Contact" page and see how many people use it.
Edit: Unfortunately, I can't get the Flash to work in my contact form. It appears Drupal strips that stuff out.