That's actually wrong, and I've been through it personally to know. Google is acting as a manufacturer and are taking warranty issues for the first year. After that Asus takes over for a second year relating to screen issues only. If Google doesn't give you a satisfactory answer Asus will.
The entire "Google won't help" started on this forum when people started "quoting" what phone reps said to them. I think we had some trolls slip bad info past us, or else Google really changed their mind after launch.
edit--
Actually however, let me add that Ebay may be an exception as others have said. If you bought it at any store (including Sam's and Gamestop) Google would still help. Ebay is considered a person to person sale so it's up to them to determine what they do. I can guess, but we don't know. My guess is that since Google tracks device activations if you are the first person to activate the device your warranty should be automatically registered. Vizio products work a bit differently and have no digital paper trail. I know that Asus is currently telling people NOT to register their warranties with them as Google has already done so. Again, we are speculating.