Web search engine launched on June 1, 2009. On July 29, 2009, Yahoo! and Microsoft finalized a deal in which Yahoo! Search would be powered by Microsoft Bing technology. A search engine maintains the following processes in near real time: Web search engines get their information by web crawling from site to site. The "spider" checks for the standard filename "robots.txt", addressed to it, before sending certain information back to be indexed depending on many factors, such as the titles, page content, JavaScript, Cascading Style Sheets (CSS), headings, as evidenced by the standard HTML markup of the informational content, or its metadata in
Database search engine Database search engine A database search engine is a search engine that operates on material stored in a digital database. Categories of search engine software include: The largest online directories, such as Google and Yahoo, utilize thousands of computers to process billions of website documents using web crawlers or spiders (software), returning results for thousands of searches per second. Processing high query volumes requires software to run in a distributed environment with redundancy. Searching for textual content in databases or structured data formats (such as XML and CSV) presents special challenges and opportunities which specialized search engines resolve. Databases allow