Here is why it is HOT! First, the program is FREE … you just can’t beat the price. Second, it allows users to create document/screen sharing sharing sessions by invitation and password protection. Third, the document is edited by one person at a time, with different colors assigned to each participant - so that you know exactly who changed what.
If this program only worked with Microsoft Word, it would be kool enough, but it works with Excel, PowerPoint, and your desktop and any application that you have open. As soon as changes are made and PUBLISHED, everyone that is logged in to the session sees the exact same document. Especially impressive is the annotative tool for marking up the screen - drawing attention to specific items/areas.
The only limitation that I see for this FREE version is that you can only collaborate with one person at a time. However, you can record (video) portions of the interaction for offline viewing.