If you have received suspicious or strange PM's from new users who have not made any posts on the forum please notify an administrator so that it can be investigated as possible spam.
To touch on this again, if you get a Spam PM or PM suspicious in nature report it (click this icon:
in the PM) in stead of emailing an admin or sending a PM specifically to one admin. The reason is a report notifies more people and will allow the situation to be handled in a more timely manner.