Bear,
This is spam mail. Unfortunately, any site that has a significant number of people attracts these spammers. This problem came up a while ago and to limit the damage they can do, I implemented two security measures. First, each person is limited to only sending 10 messages a day. Second, each message has a link that allows you to flag the sender. After a few people flag the sender, this user will not be able to send any more messages.
because these people are manually logging in and sending messages, there is no way to completely stop them, however, if everyone flags these people as soon as getting one of these messages, then it will make it extremely difficult to do any real damage.
Lastly, each user has the option weather to receive any emails through your profile. So if you turn it off, then nobody can send you any messages.
I actually have a whole private messaging system almost done, but i have been rather burned out recently so have not been making any upgrades.
-Mike
