I've been using twitter (Twitter: What are you doing?
) for a fair while, using mainly
twitterberry client and more recently twibble (twibble :: a location aware twitter client for Mac OS, Windows, Mobile
twitter is like an instant messaging platform but instead of sending your message to just one person, it broadcasts it to people who 'follow' you.
There is a great little video on the twitter.com which explains it better than I can.
I've been experimenting with another social networking tool/site called brightkite, brightkite.com
brightkite goes a step further than twitter and does clever things like check who is in your vicinity that are also using brightkite and allows you to message them etc.
You can post pictures and do other neat stuff.
They have just released a beta client for the iPhone, which has been in great demand. They have a blackberry client in the works but it is far from ready at the moment. I'm not sure they realise there is a demand for it.
If you start using brightkite you sill see how neat it is, give it a few days though before you dismiss it. You can use it on your blackberry by using the mobile interface, which works fine in the rim browser.
brightkite allows you to post to your twitter account from within brighkite too.
It's invite only at present and I do have a spare invite or two to give out.
Let me know if you are keen to give it a whirl.
If we can drum up a bit of interest on here maybe the guys developing the brightkite app will push it forward a bit ;)