I've seen that some people is posting his / her e-mail in the messages. Well, unless you want spammers to send you lots of unsolicited e-mails, don't make the job of their spambots easier. A spambot is a small computer program browsing the Internet in search for e-mail addresses. Everytime they find an e-mail address somewhere (in a bulletin board, newsgroup, even on a web page), they add it to their database of "victims".

It's safer to write your e-mail in your profile, since you have to click on a button to see it and spambots don't do that (as far as I know).

Regards,

Antonio