Some people say: "but the computers become faster every year," to which I respond: "but the amount of data we throw at them grows every year at a similar rate."

There will never be a substitute for good algorithms. In my field (bioinformatics), thanks to next-gen sequencing technology, the data growth actually outpaces Moore's law. I imagine the same is true for data collected from social networks.

You have reminded me of that old line: "What Andy giveth, Bill taketh away."

(Referring to Andy Grove of Intel CEO fame 87-98, still there in some capacity, and Bill Gates.)

It depends. There are still corporations making real money that could fit all their essential data on one such machine.