I have had a couple of reports of members receiving PMs from new members they don't know, often in Russian (Cyrillic) and with a link in the message.
These are spam posts DO NOT CLICK THE LINKS!
We have a safeguard on this site that stops new members from starting a thread on their first post without it being approved by a moderator. However, it seems that these spammers can quite happily post PMs to members without approval.
Hopefully we will come up with a countermeasure, but in the meantime, if you get a PM and you are unsure, do not click any links and either notify a moderator, or delete it if you are certain it is spam.