Search Engines
A Search Engine is a program that performs two basic functions:
- “Crawls the Internet” building an index of URLs and key terms that characterize the content of the page
- “Lists the URLs” associated with a given set of key word terms according to the index
Crawling is an ongoing activity to keep up with newly added pages and to prune broken links
Listing is performed on demand from users
The effectiveness of a search engine is related to the amount of
the Internet that it has “seen” and how discriminating its index is