When I first came across this, I thought of a prank an ex-coworker at a previous company played on a couple people. When someone would leave his/her desk, this guy would go hook up another mouse in an inconspicuous location. Then when the person gets back, the guy would start messing with the victim's cursor. (NOTE: two mice controlling one cursor and you can imagine the results..) First, it was subtle and done ever so slightly so that the victim would think it was a minor tweak with the wireless mouse. But of course, the victim would eventually figure it out either from drastic movements or the laughter coming from the guys.
Anyhow, that's what I was thinking when I came across Microsoft Multipoint. The press release can be found here. It is being touted as having great educational implications for institutions that lack the hardware infrasctructure. What it basically allows people to do is to have applications that respond to multicursor/user inputs. As a developer, you would be handling the response to multi mouse thread events.
Besides the education sector, I can see tremendous potential in the gaming arena. It would range from casual games to hardcore gamer titles. Recall the casual Photo Hunt game in your typical university arcade? While you could participate with multiple players, it could only handle one input at a time. Granted, it is a different scenario because it is composed of a touchscreen; but you can imagine a PC version (not tablet PC) of that game. If you are interested in seeing something cool on multi input touch screens, you can check out this video here. Nevertheless, with the upcoming sneak peek at Multipoint in Jan 2007, it is making the possibilities a reality for developers.
In fact, as noted by a PUM speaking on Channel 9, it may even spread to the graphics industry when doing image manipulations .
With all the possibilties for applications to take advantage of Multipoint, you can just see the can of worms being opened for UX and usability.
Nevertheless, this is definitely an exciting time to be a developer with free product lines such as XNA Game Studio, Robotics Studio...
If you are student, you can sign up for Imagine Cup and check out Multipoint at: http://imaginecup.com/multipoint/default.aspx. They will be releasing an alpha SDK for Multipoint in Jan 2007. This will be followed by subsequent CTPs. And if you are not a student, you can sign up as a guest (which is what I did) and hope to get in on the Multipoint news. The theme for this year is "Imagine a better education for all!". I would definitely encourage students to get in on this as one of the rewards for having the most innovative Multipoint enabled idea will be an internship with the team responsible for this at Microsoft.