Info on the Caffeine Update Google recently opened up a preview of our new Caffeine update, and I wanted to give a little more background on this change. At the Real-Time CrunchUp a few weeks ago, I joked that the half-life of code at Google is about six months. That means that you can write some code and when you circle back around in six months, about half of that code has been replaced with better abstractions or cleaner infrastructure. Six months is an exaggeration, but Google is quite serious about scrutinizing our codebase regularly and rewriting the parts that don’t scale well to make...

By Matt Cutts People think about PageRank in lots of different ways. People have compared PageRank to a “random surfer” model in which PageRank is the probability that a random surfer clicking on links lands on a page. Other people think of the web as an link matrix in which the value at position (i,j) indicates the presence of links from page i to page j. In that case, PageRank corresponds to the principal eigenvector of that normalized link matrix. Disclaimer: Even when I joined the company in 2000, Google was doing more sophisticated link computation than you would observe from the classic...