As bizarre as this sounds, one of the most valuable innovations in technology over the last several decades is Facebook's "Like" button. That's what has propelled the company to a galaxy-orbit valuation for its forthcoming initial public offering, filed Wednesday.

This is not only because the word "like" is, like, the identifying word of an entire generation. It's because computing has evolved beyond just taking directions from humans—and instead is cozying up to us and sniffing out our emotions and intent.

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