WikiEducator Notes: OERu's course feed aggregation and messaging system
Here at the OERu, we provide a service, attached to all of our online courses (and available to all of our partners - or anyone else for that matter) which allows anyone involved in those courses to communicate with their peers from any one of a dazzling array of online "places" with WikiEducator Notes (aka WEnotes). The entire system is free and open source software (FOSS).