Build your own search engine

You can create a search engine that concentrates on a subject of your choice and that prioritises or restricts search results to websites and pages that you, or your friends and colleagues have specified.

Google Custom Search allows you build a search engine for a topic of your choice that either searches the entire web, prioritising results from web pages you or your colleagues have specified, or searches only those pages you have specified. Look at the examples of how this works.

Rollyo allows you to create a search engine that searches a web sites selected by you on a subject chosen by you. To see how this works look at Brian Greene's String Theory Search Engine.

Other examples include Swicki or Yahoo Search Builder.

These tools are free but will need to register to use them.