Google update recently and our page rank goes down? How does google evaluate the site for page rank? It is the value of backlinks or the quality content?
Backlinks plays a big role in increasing your page rank. Actually, a site can have just one page of content and still have a high PR if it has a lot of backlinks.
The PageRank of a page is based solely on the number and quality of the links that point to it. The content of the page does not affect the PageRank score. A drop in PageRank generally means that the number or quality of the links that point to the page have dropped. But a single point drop can also simply mean that Google has recalibrated the PageRank scale to account for the growth in their index and not that there has been any significant change in the links involved. I think its very likely that Google has done a recalibration in this last update, so if you only saw a single point drop in your PageRank score and your rankings in the search results has remained steady over the past couple of months, I would not be overly concerned. Still, up is better than down and its always a good idea to keep working on building good links.
Mostly true, but not 100% correct. I know for a fact that sites that update frequently + get good backlinks are better at getting PR scores.
rainborick is spot on with his explanation. Absolutely nothing to do with content/update frequency. It's just backlinks, and the PR that they themselves pass.