Yes of course (and it is not a charity project, either). The fact that you are linking ReCaptcha to a valuable data stream for Google seems to support the my general claim that Google is deriving value from the data stream.
And perhaps the collection of that data almost exclusively at times when a single identity can be correlated with a single datum ( i.e. account creation and management) is merely coincidence.
But surely you are not suggesting that Google is ignorant of this fortuitous situation and its implications for their online advertising business.
No, I'm not. From the wording of your question I thought you didn't know they digitized books, which is a revenue stream already. They might use it for other data indeed.
