Web search engines are now part of our daily lives. Without them around, our life will be a little more chaotic. Ah-hah. As I can see it, search engines will linger for the longest time.

We use them as often as we want to but do we know how to classify them?

Well, when I say search engines I mean web sites that provide a search facility. And there are lots of search engines around. Let me give you the kinds of search engines...

Automatic
Automatic search engines are based on automatically collected, sorted and analyzed information. Their crawlers/robots/spiders read web pages follow links at the same time collect info. The data gathered is analyzed into an "index" where the results of your queries depend.

Directories
These search engines are based on info gathered by human editors. The latter decide which websites to include in the list and in which categories. With directories, editor's impression is a big factor.

Pay-Per-Click
PPC search engines allow you to pay to be listed for relevant keywords. But there are some guidelines that are to be followed accordingly. The overall amount you pay is based on a combination of your traffic and results.

Meta
meta search engines combine results produced by other search engines. They use mixed methods to generate results.

There you have it. Now you are familiar with the classification of search engines you use on a daily basis.