Search engine optimization
Search engine optimization is a way to make websites appear in the search engine's results pages (SERPS) such as those given by Google. Many people use search engine optimization companies to do the work for them because it takes too much time to do themselves.
A more common word used to describe search engine optimization is internet marketing or search engine marketing.
Search engine companies are careful to watch that spam does not affect their search engine results pages by adding filters such as Google's PageRank.
Most people do not need to pay for search engine optimization services because usually a website is supposed to show up on the search engines over time anyway. But some online shopping websites may want to show up sooner, and so they pay for search engine optimization from companies that provide it.