Lots of rumors today that Google Base is an eBay-crusher.
Nope. It's free web hosting.
Google uses a lot of bandwidth indexing other people's content. They could save a lot of money by having the content tell them when it's changed instead of having to check. So much money that it's cheaper for them to just host it all. And you know, for infrequently-accessed content, this makes a lot of sense.