I've just been checking my Google Reader subscriptions., and came across this interesting post from Social Guy. It contains 50 'netiquette' rules for students, categorised into General, Twitter and Facebook. Helpfully, there are sections devoted to job-seeking and grammar as well.
I don't agree with all of these 'rules'. For instance:
Substituting “2″ for “to” looks like you’re in junior high.
Well, perhaps, but it also saves one character, which could be crucial!
You might think it’s nice to send an automatic message every time someone follows you, but it actually makes you look lazy and unengaged. Social media is about the personal effort behind the connection.
I agree, but not responding at all for a while also makes you look unengaged.
I shouldn't use this set of rules completely out of the box, but as a very useful starting point for discussion with students.