In the newspaper here there was a good article by Theo Stielstra called 'mailen is voor oudjes'. Henk Blanken also blogged about it. Stielstra states that mail is for the elderly (in this case 25+!). Students communicate via MSN, SMS and Hyves. A 15-year old is quoted who says that she uses email at times when she has to send files to fellow students for school. Another had the experience that she thought she wasn't invited to a party - but hadn't checked her mail for a long time! Another example (as I blogged before) of exclusion through choice of technology.
So why don't they use mail? Mail is old-fashioned and slow. Writing mail ressembles work.
I must say I recognise the way mail for me is the baseline, if a forum doesn't have alert, at times I forget to check it. I participate in Facebook through mails. Our babysit (17 years) complained once her friends don't reply to her mails frequently (this article explains why!). That shows that even amongst the youngsters, there are huge differences.
Conclusion: communication is getting easier, and getting harder.