A future of frictionless, continuous shopping fits with Google’s vision for a world where we no longer need to search for anything, since we ourselves are perpetually monitored, with the relevant product or information sent to us based on perceived need. “Autonomous search,” they call it.

Ray Kurzweil, Google’s director of engineering, even wants to give us a “cybernetic friend” that could satisfy our wants before we are aware of them. By monitoring our conversations, e-mails and reading habits, he said, “it may pop up and say: ‘Well, you mentioned two weeks ago you were worried that vitamin B12 isn’t getting into your cells. There was new research just released two seconds ago that speaks to that.’”

To Mr. Kurzweil, who once confessed to taking 250 nutritional supplements a day, this might be a useful service. As for the rest of us, I’m not so sure: according to Google Scholar, 13,000 scientific papers and books that mention vitamin B12 came out last year alone. […]