I'm with ChooChooGuy here. It's most annoying when a buyer is viewing your listing, and is also being advertised the same item from another seller.
I was checking my Half.com shop, and doing some testing around, and thought I would add a few items to the cart. (I was looking at shipping rates on multiple items.) I noticed when I was sent to the cart page, and it says... Buyers who were interested in this title were also interested in.... and it listed the same darn copy of the book from another seller. Not cool...but technology isn't perfect.
If anyone is so inclined to view this test, they can check it out themselves at: http://shops.half.ebay.com/ldcdesigns
I'd be interested to know if another "shopper" got the same result.