This document defines and describes different types of search engines. It begins by explaining how search engines store websites in their databases and index the web. It then defines search engines as tools that help retrieve information from the internet. The document outlines four main types of search engines: crawler-based engines that use software programs to index websites; directories that categorize websites by human editors; hybrid engines that use both crawlers and directories; and meta search engines that combine results from other search engines. It concludes by discussing advantages like enabling quick searches, disadvantages like information overload, and limitations like not being able to index the entire web.

1. SEARCH-
ENGINE

2. Contents
▶ Basics of Search Engine
▶ What is Search Engine ?
▶ Types of Search Engine
▶ Advantages
▶ Disadvantages
▶ Limitations of Search Engine

3. Basics of Search Engine
1. Store millions of pages in their data base.
2. Sites are included automatically based on a set criteria no human interface.
3. Search features / scope vary greatly from one to another .
4. Good for beginners and experts .
5. Good for searching on a narrow topic.
6. Search for particular types of documents ,files etc. is possible.

4. What is Search Engine ?
▶ The father of search engine is Jonathon Fletcher.
▶ Search is a tool ,which helps in retrieving in information
from the internet .
▶ It indexes the web and accordingly builds its database.
▶ Each search engine has its own set rules to index
websites.

5. Types of Search Engine
 Crawler based search engines
 Directories
 Hybrid search engines
 Meta search engines

6. Crawler based search engines
▶ Are search engines that use software programs that are called “spiders”,
“crawlers”, “Robots”, “bots”. These programs can access the webpages
to categorize and analyse them and then add them in the search engine
data base , where any user can find them when searching. The crawler
based search engines are constantly updated with new webpage that
would be available in their database.
▶ Examples:
1. Google
2. Yahoo
3. Ask.com

7. Directories
▶ Are websites sectioned in specific categories by human
editors and are then place in the “Directories” , database.
▶ Examples:
1. Yahoo Directory (www.yahoo.com)
2. Open Directory (www.dmoz.org)

8. Hybrid search engines
▶ Are search engines that use both crawler based searches
and directory searches to obtain their results.
▶ Examples:
1. Yahoo.com
2. Google.com

9. Meta search engines
▶ Are the search engines that combine all the result from
other search engines into one big list.
▶ Examples:
1. Metacrawler
2. Dogpile

10. Advantages of Search Engines
▶ Enable to quick search to vast amount of information from
one search box.
▶ Search on a specific type or piece of information is
possible.
▶ Different types of search engines enable to look for
specific types of Documents.

11. Disadvantages of search engines
▶ Creates information overload
▶ Semantic search is not possible
▶ Privacy and security is of concern
▶ Makes everyone to dependent

12. Limitations of Search Engines
▶ Can not index the entire web. Most of the search engines
can index only between 40% and 60%of the web.
▶ Can not index sites governed by password and developed
using frames.

13. CONCLUSION

14. Thank you