Thus, as students add and drop your course the class email list is automatically updated. Keep in mind that not all students read their email on a daily basis. So if you're going to be using your class email list to send out important or time-sensitive messages you'll want to make sure your students know beforehand. It would also be good to let you students know whether or not you'd like them to use the list, and if so what sort of messages would be appropriate for your course. A class email list can be very useful but it is not the end all and be all for electronic communication with your students.
Email based discussions are often hard to follow with a large group.
Caucus, our web-based conferencing system, provides a little extra structure that makes this sort of activity much more effective. In theory you could send files as an email attachment to the list. In practice this is very problematic. Every student will have to decode the attachment which can often lead to confusion. Also, attachments sent to many people can overwhelm an email system.