But when you're as big as Google, what businesses are worth getting into?
How much does VISA take in per year? I dunno, but I'm pretty sure if you want a money fountain to finance an altruistic geek nirvana, that's the kind of revenue stream you want.
Where support by advertising is a poor fit you need a way to keep the lights on. Charity and community spirit work for some efforts, but some things require the luster of cold hard (micro) cash. For the information economy to become a reality, this is a requirement. Many others have tried and failed, but if anyone can make micropayments work, it would be Google.
There's a mint to be made data mining the nation's (or world's) medical records. Just collect the data and lease it back to the pharmas, biotechs, and academic researchers. The big roadblocks, which Google might have enough good will to overcome, are (justifiable) privacy concerns and the pathological motives of vested interests in the field.
Ok, I guess the GOOG is way ahead of me on both of these...