I believe at least the readers of my blogs understands what are search engines ,If not I will site one of the many example which will give an idea what is search engine for example “Google.com”, by definition search engines are program that search for items or words in a database, it searches information in the world wide web, these search results often shows in result pages ,the search pages will contain a mix of web pages, images and other file types including advertisements .if you think google is only search engine it is not search engines are many famous once includes Google, Yahoo, Bing and few other which you are not much familiar like Duckduckgo, Bleko, Cruchbase, EC search etc .
Search engine are not limited to these few examples I mentioned they can be categorised based on country, region and even on specific search types .many of these search engines die out in few year since owners of these start engines loose the enthusiasm in middle of their struggle to market their product .Few examples I will site based on geography and few of the non-active search engines as well.
There are general search engines,P2P(peer to peer) search engines, meta search engines, geographical limited scope search engines, semantic search engines,accountancy,business,education,fashion,foo/recipes,genealogy,fashion ,mobile ,job ,legal and search engine are there for information types and some search engines are multilingual some are single language for example ”Biadu” is Chinese/Japanese were as DuckDuckGo is multilingual,P2P search engines are application search engines that partitions tasks between peers FAROO is an example of P2P.meta search engines is a search toll which takes the help of other search tools to get the data DOGpile, DEEPERWEB can be taken as an example to meta search engines.
Based on geographically limited scope DAUM can be taken it is the search engine in Korea or Walla! Of Israel as I told you before there are various types of search engines for every purpose. Now I will tell you about few search engines which has died out like for example Alta Vista which was acquired by yahoo and shut down in 2013, some search engines for example MYRIAD SEARCH, LEAPFISH etc no longer exist, there are many in this category for active and inactive search engines .If you are looking for the names and number just check in Wiki you will get it.
Good search engines makes a lot of money, How they make it is through pay per click technique ie, search engines will be running add along the organic search engine results and when someone clicks on these ads they make money, since search engines make money website owners to make them, not everyone makes money from websites only websites with traffic and advertisements makes them or else it should be a product seller/e commerce websites.