I see Andrew posted about the RD article. There are quite a few scams out there involving both Nigeria and Ebay, basically, if it doesn't past the sniff test, and smells a little fishy, it probably is.
I know we were contacted by a buyer, from out of the country, who wanted to pay by Western Union, more than the purchase price of the item, and he wanted us to refund us the difference. We reported him, but I don't know how much that helped.
It's my understanding they usually go after big ticket items, usually but not always. And electronics is another area where there's a lot of fraud. A few years ago we bought a DVD player off Yahoo auctions, and I paid with a USPS Money order, but the guy took the money and ran. Fortunately, because I used a postal money order and the man who cashed the money had a different name than who I was told to make it out to, it was considered "stolen" and I was able to get my money back through the PO. I did track a phone number down, through the New York address I made my payment to, and wouldn't you know it, the lady with an accent on the other end of the phone had "never heard of the person".

But maybe my phone call did make her heart skip a beat.
[Edited on 3-24-2005 by ChristianasJourney]