Second Life
I have used second life both for personal entertainment and previously in a programming class.
I actually like Second Life a lot in theory. Its a great idea to be able to go somewhere and collaborate or learn in a group environment, especially for distance students. It allows us some sense of who our classmates are and get an underlying look at their personalities through their choice of avatars and chatting with them.
That said there is a whole lot about second life that I actively dislike. For one I think it has been massively overhyped in the library community. For one reason or another (probably because the experience provides great anecdotes and appears cutting edge) it has been quite widely embraced by a wide spectrum of librarians. People who I had a great amount of trouble pointing out the benefits of delicious too were immidiatlely sold on Second Life. However the actual benefits to patrons can be close to neglidgable.
I have yet to meet a patron (including active gamers) that have mentioned second life or being interested in it. Therefore, using it to go where the patrons are is not really a reason to invest in it. In addition the computing requirements are really high, therefore putting the digital divide in bright perspective. I was not actually able to use my fairly new work machine to get on the grid and had to use my brand new home machine to get around.
I think products such as Elluminate and IM can be used very similarly without taxing the resources of our patrons or our IT departments.
