More than 48 billion pages of information was indexed by search engines. That is hundreds of thousands results for each search query. And it's not just about the text, that are maps, documents, images, audio or video data. Today, the search engines have a much more serious problem than the indexing and ranking pages. Google does not want just to show search results - he wants provide own answer on your questions. He wants understand when you search for a man to know what his name is, who he is, is doing what and where he lives. If you are looking for a bar - it will try to find near place where you are now and show it to you on the map. This is true for many of things: books, movies, music, events, shops or businesses. Maybe not as often, but you should already have seen it - if you do not understand what it is about, try search for "Madonna" or "Odessa". Google works hard, and if your request is appropriate and Google has data for it, Google always displays such results on the first page, and no matter how much result fit on it or it does not fit.
You can achieve deeper mutual understanding between your site and the search engines by applying the principles and technologies and pricipals of Semantic Web concept. This is a set of open standards and guidelines for structuring and presentation of information. Search engines are able to find such blocks on the web pages, they are better indexed and allow more accurate content delivery. By itself, semantic data does not affect the relevance of your page or its rating. If you have great and well-formed content, it will help you break through other results to the first page.