Currently we have only three options ie Twitter, Facebook and Google+. It will be great to have a mail-it option there. Sometimes I discuss some issue with my friends and while browsing on Stackoverflow on my iPad or Mac or iPhone, I see the same issue discussed on Stackoverflow or some nice post I check on Stackoverflow and I want to share it with friend.
Now in order to send it via email, I want have to copy the title the question in subject or manually type the subject and in content I specify mail is just URL of that Post. It will great by pressing a icon most of the things are pre filled and I just type friend's email and its done :)
PS: Heights of lazzines, but it will good to have this thing :)