It means that our ranking algorithms have good recall but very poor precision. We value web page connectivity more than its content. We don't know how to teach machines to evaluate web page for its merit so we hope that a large number of Twitting, Liking and Plusing non-experts will approximate single expert. Millionshort shows that this model isn't good enough.
We value web page connectivity more than its content.
That's pretty much precisely how PageRank (in its original form) changed web search. At the time, at least, it worked because we were really bad at automatically analyzing content, and the connectivity signal provided better results.