You nailed it when you said the shop you want is full of stories - because stories are created by people, not automated recommendation engines.

Maybe Amazon "knows" our thoughts, as Ross Hudgens commented above, but people are still much better at selling, even if automated recommendations are superior. Human's just aren't rational in that way - we trust other people more than we trust algorithms.

If you could get instant and relevant opinions by people you feel you can trust as a response to your every query, now that would be a Google-killer. Yahoo Answers is nowhere near that of course, and neither is Mahalo. The barrier to Twitter/Facebook delivering that right now is what some commenters here mentioned - that unless you're a twitter celeb with lots and lots of connections, you're unlikely to get instant good responses.