Definition:
Canoo WebTest is a free Open Source tool for automated testing of web applications in a very effective way. Defects in your corporate website may be only annoying at one time but they can cost you real money at other times, they can lower your market value and may even put you out of business. Canoo WebTest helps you to reduce the defect rate of your web application.
Further Reading:
Book: Agile Testing by Janet Gregory and Lisa Crispin.