Curious as to how Google searches and brings back the most relevant results to your entered criteria in half a second? Well Matt Cutts, head of Google's web spam team has provided an 8-minute video answerind that exact question.
Answering a question submitted by RobertvH from Munich, Matt details the key three steps to the search engine's success: web crawling, indexing and ranking on relevance. He goes on to detail how the crawling part of that process has evolved from the slow, clunky fashion of content discovery, to the more recent iteration that allows for quicker ranking via breaking the web into easily digestible chunks.
If you are interested in SEO and the inner workings of the Google search engine (something which Matt manages to make for a really interesting watch in the video), this is just one of many different videos which answer questions posted on the Webmaster Forums, so post a query and check out their YouTube channel.