The web is a great, layered entity with search engines to search for things in its every corner. There are the big name general search engines like Google, Bing and Yahoo; although these are general web search engines, they are often more than powerful to drag up any little titbit from the web. For instance, the more specific someone gets with a search the more clear the search results will be, so instead of searching for auto insurance company, use specific names, search under the new tab, or try inexpensive auto insurance company or auto insurance discounts.
These programs also have selective search engines for image search, financial and stock related news search, video and ebooks search, and a host of other features that makes them enter the domain of the selective search engines. However, the latter in their independent forms also have an important place on the web.
Among selective search engines, the most important ones are job search, people search, business and accountancy search, medical and legal, television, news, property and video games search, as well as the popular bittorrent search.
Job search engines are very popular. Millions of people get jobs by searching online. Most important of all job search engines are probably the trio of Craigslist.com, Careerbuilder.com and Monster.com. Of these, the latter two are dedicated job search portals, while Craigslist offers job searches as one of its many kinds of searches. However, craigslist job searches are probably one of the most popular ways of searching for jobs in the USA. It is also slowly becoming popular in many other countries.
In the legal field, Westlaw and Lexis are extremely diverse, exhaustive and encyclopedic legal caselaw, news and other information search engines, with databases for the US, UK, EU and elsewhere. These are almost indispensable for legal professionals, especially in the US. There are regional legal databases of similar nature, for example, Manupatra, which caters to the Indian lawyer.
These are just some examples of how specialized search engines have become so important in the internet searching domain, and for many, some of these are indispensable.