I have been involved in several discussions related to building an online community that connects students with research and practice. This community would live outside of the classroom and the learning management system and could include alumni as well as current students and teachers. Several teachers are using Facebook or Twitter to connect with students and other professionals. These communities seem to work well because it is something that students already check. They are already invested in Facebook and many to Twitter as well, so there is no extra effort. We are looking for a more system-wide solution.
In doing research, I came across a great EDUCAUSE article that has been very helpful to the process. If you are looking to build community in your school, classroom or university, this might be a good starting point.