Ive been playing with Twitter recently. Its a social networking tool that allows you to share updates with other users and stay in touch with your friends with quick snappy statements or questions. You can follow multiple users at which point you see all of their updates. Users following you will receive all of your updates and can reply if they wish. It can become rather addictive. You can get twitter clients for multiple devices including your Blackberry (Twitterberry) , PC or IPhone etc etc.
The tool can also be great for networking and reaching out to a wider global audience. Learn from your twitter buddies and share, share, share.
Feel free to add me on twitter. My twitter ID is http://www.twitter.com/millionaireblog