Wired magazine has a feature article which gives about as much detail as outsiders can expect on the core of Google’s business, its search algorithm. I was surprised to see that philosopher Ludwig Wittgenstein was an influence. Hundreds of different pieces of information (or “signals”) are used to rank the results, and some of these are contextual to the user: for example, geographical information is used to prioritise results from near your location.
One of the signals which is increasing in importance is page speed: the time it takes the page to load and render. Hence it’s worth reading up on Google’s performance optimisation tips.