Search engine marketing Search engine marketing Search engine marketing (SEM) is a form of Internet marketing that involves the promotion of websites by increasing their visibility in search engine results pages (SERPs) primarily through paid advertising. SEM may incorporate search engine optimization (SEO), which adjusts or rewrites website content and site architecture to achieve a higher ranking in search engine results pages to enhance pay per click (PPC) listings. In 2007, U.S. advertisers spent US $24.6 billion on search engine marketing. In Q2 2015, Google (73.7%) and the Yahoo/Bing (26.3%) partnership accounted for almost 100% of U.S. search engine spend. As of 2006,
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