I think this has been mentioned before, but another warning won't hurt.
I have been watching the 'Who's on-line' page a bit recently, and there is often a guest who is looking at someone's profile. Can't tell if it is always the same guest of course.
This may be quite innocent, and if it is, apologies to that (or those) guest(s), but it may also be someone trawling for email addresses.
If you don't want tons of spam emails etc, make sure your email address is 'hidden' in your profile.
Del