diberry - 8:26 pm on Aug 23, 2012 (gmt 0)
There's nothing as impartial or more up to date than the collective views of your visitors.
Google isn't in a position to measure enough user metrics with enough accuracy to rely on them alone. Hence the use of links and so on.
Building for visitors is not enough. Being great isn't, either. Marketing is key, and it's got to go way beyond Google.