Google was a better search engine than it's predecessors for a number of reasons, but probably the most well known one is PageRank, the algorithm for measuring the importance of a page based on what links to it. Though not necessarily that useful on its own, this kind of link analysis can be very helpful as part of a general information retrieval system, or when looking at any kind of network, such as a friend graph from a social network. Read More »
A site about search, text categorisation, clustering and other interesting topics relevant to the web, but not often covered for PHP developers.