WebSite Content Checker allows you to track changes across websites you own, or just want to stay in touch with. With an easy and intuitive interface you can add your sites really quickly and get notified whenever the content (or a part of the content) changes. It can inform you with a message like 'The content of site MySite has changed', the site content, or the site content processed by a bash script. You can write your own bash script to override the page content so you can for example filter out the weather from a weather forecast site or whatever.
The main aim of this app is to use it with connection with your own site, and a special server-side script which will for example tell you how many items you have in the administration or so. The app then checks for changes and when the count of items get changed you'll get notified so you can go there and... But it can also be used for other purposes, and I think you'll find a LOT of them ;)