Webspector is a Internet research and navigation tool that automatically tracks web pages for content changes. Webspector automatically navigates a number of user-defined lists of web pages, either by button press or on a schedule.
Monitor up to 200 web pages.
Reporting features, including reports of errors and notification via e-mail.
Keyword highlighting of user-defined words and phrases within each page.
Import bookmarks from existing browsers.
Flexible scheduling capabilities.
Link Wizard automatically extracts and imports URLs from any web page on the Internet.
Advanced filtering options for reducing clutter in your web inboxes.
Priority technical support.
"Webspector Professional Edition ($99 US) all of the benefits of the Standard Edition, but with the ability to monitor up to 500 web pages. Webspector Enterprise Edition ($299 US) all of the benefits of the Standard Edition, but with the ability to monitor an unlimited number of web pages.
The free version of Webspector (with less features) is available for download here"