The workflow is simple - download and install the Tahiti software (~2.5 MB), login with your Windows Live ID and you are ready to share your entire desktop, web browser or any program application with the world.
The desktop screen can be simultaneously shared with upto 15 people at a time and the person sharing can give control to anyone else who's also part of the screen sharing session. And each participant has a personalized mouse pointer to point out specific items or highlight an area of shared screen.
Tahiti is tighly integrated with Microsoft Word and it may even be an attempt by Microsoft to counter the GTalk chat feature of Google Docs. With Tahiti, you can share a Word Document and every edit made by a participant can be identified with the participant’s name and timestamp.
Not just the screen, Tahiti will also let you share files, presentations or images which other participants can download during the screen sharing session. That's a useful feature because you don't have to upload files to a third-party site like rapidshare or send them as email attachments.
The shared portion of the screen is brighter than everything else to visually suggest what is curently being shared.
Microsoft may be planning to add audio features in Tahiti but until that happens, you can use your VoIP software like Live Messenger or Google Talk to share and speak at the same time.
Unfortunately, there isn't a way to record the screen sharing software without using a third-party software like Camtasia Studio or Wink.
Some may think Tahiti as a poor cousin of WebEx or Microsoft Live Meeting but it is still useful and powerful enough for most non-corporate users.
Microsoft Codename Tahiti | Download Tahiti [Thanks Abhishek]
Related: Live Screen Sharing with Skype
Update: Microsoft has closed the Tahiti beta program for new users. If you are already running the pre-Beta release, the service will continue to be available. An official version of Tahiti is expected in mid-April.