I ran into this scam while trying to sell my daughters Bug and wanted my compadres here to know about it also.
There are many people who have been exposed to a certain type of car purchasing scam being perpetrated to some sellers listing classified ads on a site called thesamba.com (it's a volkswagen site). I'm afraid it could spread to miata.net at some point so beware.
If you go to thesamba.com home page, upper left hand corner of the screen is a link to take you to a full description of this 'classified's scam'. The short version is, foreign buyer, eager to buy car w/o much scrutiny or haggeling however, they want to send you a (bogus) cashiers check for considerably more than the purchase price hoping that you will trust the check, deposit it and forward them the balance to their shipper or to them. Anyway, something seemed fishy, I came across this info and it explained it all.
Hope this helps get the word out a bit.
Chris
74 Super Beetle still for sale :-( to legitimate buyers 92BB&T