I think one of the biggest problems is the insane level of reliance Google now has for domain authority.<p>It feels like a cheap cop-out for controlling spam: the side effect is that you have heavy hitters like Maholo, Target, etc... all out spamming the more relevant websites.<p>A more general example of this algorithm problem is that it ranks the pages of Digg, HN, or similar to be higher than the actual website it links to, and most of the times those pages are devoid of any actual content, merely containing a couple of votes and no comments.