I was thinking something along the same lines. PageRank was great back in the day, but in today's world, the link is not the only way of determining whether a site is good or not. I wonder if a rethink of the HITS model or a complete overhaul of search ranking based on social and reputation cues is in order?

StackOverflow does well despite few people linking to them because the search terms are so niche, if I search for a fairly generic programming term I maybe get one StackOverflow post in the first 10 but if I search for an error message, they'll all be SO. Other StackExchange sites maybe don't benefit quite so well from that long tail, though. Sites like Quora presumably have the same problem.

It's interesting how sites like these, and in turn mobile apps, are turning information into vertical silos (which want you to stay within their bounds) rather than the horizontal web of equality we're used to.

(Also, the interns are pretty well paid, but yes. They start out as autocompleters: http://www.youtube.com/watch?v=blB_X38YSxQ)