How many parameters does Google consider in their algorithm? Used to be about 100 in the old days. Now it appears to be 250 parameters that factor into your page ranking:

Gupta chisels away at the PageRank algorithm simply by looking at what the No. 1 ranked sites are doing. “We have identified 250 parameters that Google studies to rank a site,” he says. “We’ve got labs where people are constantly monitoring the impact of each. But the birds-eye view is, how can we make a site simply perform well in the natural course?” source