Hello,
I've seen many web hosting companies make you list the last 3-digits on the back of a CC.

What does the last 3-digits of the CC provide?

Thanks!

I think it just proves the card is in the physical possession of the person placing the order.

My original thought was correct:

CVV(II) = Card Verification Value '2' is a set of three digits, found only on the signature plate on the reverse side of most credit cards, that is unique to that card. By requiring that your customers enter this value you are adding a very important layer of security to every transaction on your site. Since the CVV(II) is found only in this location, the card is more likely to be present and therefore there is a reduced risk of fraud (i.e. stolen charge receipts from department store dumpsters, intended to be used to fraudulently purchase goods online, would not reveal the card's CVV, and therefore could not be used on sites supporting this routine.)

In some cases it's not the last three digits of the card number. You can usually find it on the back.

I think it's a pretty good idea.