Back before RSS became so common, I there was a site that watched web pages for me and sent me the text that changed each day-- that site stopped working and I don't remember the name anymore.
There are still pages on the web without RSS feeds, what need web watchers (with web clients or otherwise) are there for me to turn to?
Google Reader (www.google.com/reader) has some support for sites without RSS. See their blog post titled, "Follow changes to any website" for more details.
It might be worth checking this extension out if you use Firefox: https://addons.mozilla.org/en-US/firefox/addon/4337/
This extension adds a small Delta icon to your browser status bar. When you click onto it, it highlights all changed text contents of the current page (since the last time you clicked onto it). Clicking again cycles through the changes. Rightclick onto the icon allows you to add scan or ignore regions and manage pages known to SiteDelta. Furthermore SiteDelta can regularly check its known pages for changes and inform you whenever one of them was updated.
