1. McLean 20061 HIGHER COMPUTER NETWORKING Lesson 7 Search engines Description of search engine methods

2. McLean 20062 HIGHER COMPUTER NETWORKING What You Should Know About Search Engines Search Engines A Search Engine is a web site which contains an indexed database of information about a large number of web pages. Crawler Based These search engines use programs called spiders which crawl through the web looking for pages which are linked to sites already stored in it’s database. When a new page is found it’s Meta Tags are added to the database. Google is an example of a crawler based search engine. Directories These search engines rely on humans to regularly update and add to their databases. When a user query is entered the search engine only looks for matches in the description submitted. Yahoo is an example of this type of search engine.

3. McLean 20063 HIGHER COMPUTER NETWORKING What You Should Know About Search Engines Meta Tags These are HTML tags placed in the header section of the page. Meta tags are not visible to the user but are used by search engines to index web pages. Meta Search Engines These search engines pass user queries to several other search engines then collate and summarise the results. This means that, theoretically, these search engine programs should give the user the best results from their query. ‘Ask’ and ‘Metacrawler’ are examples of meta search engines.