There are an enormous number of search engines in the world. Some are actively engaged in collecting, sorting and presenting the mass of information found on the Web, some are simply presenting others search results as a service to attract visitors, some fall in between.

Many are no more than fronts for someone else's database of web sites, with some different services packaged in, and a different brand. This does not make them less valid as search engines, but it can be useful to be aware of where the results you see are really coming from.

There are currently around 10 main databases in use throughout the world. Some are created and maintained by automated programs called "spiders" or "robots". These are "crawling databases".

Some are generated and reviewed by humans, and are called directories.

There is also a third category of database. Some search sites allow you to decide how much you are willing to pay to have people visit your site, and allow you to bid accordingly. These are known as Pay-Per-Click (PPC) databases.

Firstly, let us look at the current list of major databases, and which category they fall into (NB this list is correct at time of writing. It is subject to change from time to time, due to evolving relationships in the marketplace. There are also many other databases not mentioned here. The main criterion used is number of searches handled by the database per day).

Next, lets look at the search engine market, examine some of the players, and see where they are getting their results from - click on the links above for each search engine or on the links below for other major search sources:-