search technology

Modern web search engines are complex software systems using the technology that has evolved over the years. There are several categories of search engine software: Web search engines (example: Lucene), database or structured data search engines (example: Dieselpoint), and mixed search engines or enterprise search (example: Google Search Appliance). The largest web search engines such as Google and Yahoo! utilize tens or hundreds of thousands of computers to process billions of web pages and return results for thousands of searches per second. (Excerpt from Wikipedia article: Search engine technology)