Here’s a quick video (3 minutes) that shows the use of Quickmail in Moodle. Quickmail
is a popular 3rd party addon that provides email like functionality within Moodle (an alternative to the somewhat confusing default core messaging system). The video was created by Bergen Community College and is hosted on their channel.
Direct video link: http://www.youtube.com/watch?v=MJBWf_lCFLU
At Kemi-Tornio University of Applied Sciences we have used Quickmail since the 1.5 days. It’s advantage is that it facilitates emails to groups in Moodle. The downside of Quickmail in Moodle 2 is that it does not work for students, only for users in the teacher role (Despite giving the student role the same permissions for the block).