This is especially useful, for example, to find discount deals on some products or gadgets like iPod Nano, usually we search on shopping sites like Amazon, eBay or Froggle (Google Product Search).
But to find a good deal we need to check the page again and again or subscribe to the RSS feed. But unfortunately, none of these shopping sites publish feeds.
To use Page Monitor, after installing the extension, simply go to a page you would like to monitor, click on the Page Monitor icon and select "Monitor This Page". Now whenever this page changes, the monitor icon will display a notification on its badge.
Of course, you can repeat this for any number of pages. You can also change the check interval and badge color from the options page.
In addition, expert users can track changes to particular elements on the page (e.g. a price tag on a shopping site) by specifying a regular expression to match against the page's source code (the result of applying this expression is compared).
Install Page monitor (Google Chrome)