How Software agents work?

Software agents are computer programs that have specialized purpose and assigned tasks.

They can perform simple and repetitive tasks faster than human workers. They can be used for personal or commercial purposes, but can also be used in malicious attacks on users.

Google uses software agents (spiders/robots) to periodically visit web sites to index them in google search engine. An e commerce agent finds the best price for a phone model on e commerce sites

A Search engine Spider Simulator

Online chat agents search answers to keywords in a database to help users asking questions

A chatbot is a a computer program designed to simulate an intelligent conversation with human users.
Most chat bots simply scan for keywords within the input and pull a reply with the most matching answer from a database.

http://www.parnasse.com/drwww.shtml

search engines use robots to index web pages

Software agents (Bots) can be used to spread spam emails, viruses and scams.
Software Update Agents (Virus Guards)

How Googlebot Works ?
http://www.googleguide.com/google_works.html
Google's algorithm assigns a rank to each page based several factors,
1. how many times the keywords appear on the page.
2. Google looks for keywords in headings. K
3. Keywords in larger headings are more valuable than smaller headings
4. Google assigns a page rank every search result.
5. Search Position depends partially on number of other Web pages linking to target page. (vote)
6. Votes from a high-ranking Web page counts more
7. The more links a Web page sends out, the more diluted its voting power becomes.
Software Agents used in personalised information management, e commerce, interface design, computer games, and complex industrial processes. They are computer programs that can be delegated to do some tasks. They are mostly self-contained programs capable of controlling its own decision making and acting, based on its environment.

http://www.google.lk/search?q=software+agents&hl=en&biw=1366&bih=546&prmd=imvnsb&source=lnms&tbm=isch&ei=b6PGTu-sPMO4rAfKkuGoDg&sa=X&oi=mode_link&ct=mode&cd=2&ved=0CAsQ_AUoAQ

More :
Gopher agents:Execute straightforward tasks based on pre-specified rules and assumptions
- Inform when temperature rises by 10% from its mean position.
- Alert reorder stock items
Service performing agents
Execute a well defined task at the request of a user
- find the cheapest flight to Colombo

Predictive agentsProvides information or services to a user, without being asked
- monitor newsgroups on the INTERNET and return relevent discussions
• Autonomy: able to perform majority of tasks without direct human intervention and have a degree of control over their own actions and their own internal state.
• Social ability: able to interact, when appropriate, with other software agents and humans to solve problems
• Responsiveness: agents should understand their environment and respond to changes
• Proactiveness: agents takes automatic action where appropriate.