PUBLIC MARKS with tags webpage & monitor

The free service provides 100 daily page checks and 1 hourly check. You can monitor additions, deletions, Google page rank, keywords, and sections of a page. Alerts are sent to you by email. They say they are working on a paid version of their service that can monitor 1000 pages per day and 50 pages per hour per user.

Use this page to start monitoring a page for changes once a day. When a page change meeting your criteria is detected you will be sent an email alert.