agents - briefing

What does the term agent mean?

"Russell and Norvig define it as "anything that can can be viewed as perceiving its environment through sensors and acting upon that environment through effectors." 

Alexa As you surf around the web, the toolbar will refresh with new information about the sites you are visiting.  You can use the information to learn more about the sites you visit and find other related sites.  It also has a handy search feature for quicker searching - good.
Copernic Like a meta search tool on steroids, Copernic searches 80 search engines, eliminates duplicates, ranks results with the most relevant results on top, AND automatically translates pages in 7 languages (English, French, German, Italian, Japanese, Portuguese, and Spanish - excellent.
NetSonic As you surf around the web, the toolbar will refresh with new information about the sites you are visiting.  You can use the information to learn more about the sites you visit and find other related sites.  It also has a handy search feature for quicker searching - TBD
SpyTools Amazing tools for finding unlisted numbers, Cell phone numbers and codes, email addresses, anonymous surfing and email, and the ability to monitor and be alerted to changes on web-sites of interest - excellent.