You don't get to use a monopoly in one area to manipulate the market in another.

Well, I'd say that's what Microsoft is doing. Or... trying to do.

Obviously this is hardly a matter of trust, although that's what eBay will want us to think probably. eBay may be afraid of Google and their market potential. Clearly they're not afraid of any of the other hundred sites you've never heard of outdoing Paypal (the ones on the list of Paypal-esque sites you can use), but this is Google. People trust Google, maybe even enough to switch them from Paypal. Of course, Paypal is still an excellent service, so I'm not sure if people would be like "Oh man, Google!" and switch over. eBay wouldn't like that if too many people did though.