Yammer is a new tool that we're playing with at work.
It's like a mash-up of a micro-blogger (eg: Twitter) and an instant messenger (eg: MSN) but more organisation orientated.
To avoid having to run another program to keep a track of the posts, you can integrate with your favourite IM client.
Just visit, https://www.yammer.com/account/im and follow the instructions.
We are planning to take an RSS feed of the posts and, using hash tags, produce time lines of product launch sequences, etc.