I received an email a while back that stated that I owned a certain .us domain name and that the sender owned the .com equivalent. The email offered to sell me that .com domain name for $100 and would use an escrow service to guarantee the transaction. On the surface, this would seem to be an attractive offer except for one thing: I already own that .com domain too!
While I won't waste my time following up on this, it did make me wonder about the "escrow service" that they would have suggested for this transaction. A scam in itself I would assume.
I do look at such email messages closely because sometimes they can be very useful. I had a similar situation where I owned a .us domain, got a message similar to today's message but I did not own the .com domain. A quick check showed that this particular .com has just been deleted (freed for new registration) and that the spammer would have just registered the domain and then sold it to me if I had responded. Instead, I just registered the domain myself. This has happened twice in the last couple of months!