Google Shopping Express looking for Bay Area testers
googlecommerce.blogspot.com
googlecommerce.blogspot.com
If not unless my daily purchase data can offset that revenue somehow I don't see how they can sustain this for long.
Two reasons I'd suggest: it can, and it wants to. Google is a great story and it's continuing to unfold.
It's certainly open to debate, but I'm questioning that the delivery itself is compensation enough for everything that Google is receiving from the testers. Obviously Google (and you) thinks this, but I don't agree that there's only one possible value-based assessment of the relationship.
But your characterization of it I found disingenuous: "Am I to think of Google as just another buddy who needs a lift to the bus station?"
There's no reason for the snark, and to pretend like Google is just trying to score a freebie like your hypothetical mooching friend is framing the argument disingenuously. The cost of delivering something same-day is non-trivial - Google is not expecting a freebie, though you are of course welcome to value your privacy above that dollar amount.
EDIT: Fixed typo
What, no love for the East Bay :-p
Peninsula covers San Mateo to San Jose.