Most email systems ardently fight to protect your inbox from spams. AOL reported last year that it has blocked half-trillion spams over the year. Out of these, majority of the spams are porn related or sexually suggestive. Though the article suggests that such sexually suggestive spams took a tumble last year, I am not still spared.
I am more conservative in revealing my gmail address. I give out only to legitimate sites/person so that I would not end up using it as a junk box. Still I get close to 5 spam mails per day and out of which at least one in sexually suggestive.