Other search engines

Google is a very effective search engine and has become so popular that it is becoming synonymous with searching the web. However there are very good reasons why you should not rely on one search engine:

• Search engines calculate the relevance of web pages to your search and present the most relevant first. Each search engine performs this calculation differently, and so will give different results for the same query.
• No one search engine covers all of the web. Studies have also shown that there is not a great deal of overlap in the coverage of the major search engines.
• Different search engines offer different features to aid your searching, it is worth exploring these to see if you find them useful.

If you are aware of the alternatives to Google you will be better able to make the most of what the web has to offer. Here are short discriptions of two other popular search engines.

Yahoo

Yahoo is the oldest of the major search services. It was originally based on a directory compiled by human editors but now uses a crawler based index. Yahoo is one of the leading search services in terms of the relevance of search results and the number of websites covered by its index.

Yahoo does not offer ways of limiting your research in the way that Google does, but you can search predefined categories of information using its search shortcuts. These are more likely to be useful for reference than for searching for academic information.

Teoma

Link analysis has become a common component in how search engines rank the importance of websites. The more links there are to a website the higher that website will appear in search results. The Teoma search engine takes a different approach to link analysis, it takes the subject you are searching for and identifies inter-linked communities of websites that are related to the subject, and so can identify websites that are authorities on a given subject.