Name:Distill Web Monitor (Free)
URL:https://chrome.google.com/webstore/detail/distill-web-monitor/inlikjemeeknofckkjolnjbpehgadgge?hl=en/
Description:Tool to monitor web-pages for changes
Utility:This free tool – 

• Monitors webpage or feed for changes
• Sends automatic SMS and email alerts on change detection

Special Features:

• Highlights the changes and maintains its history

Same add-on for Firefox -https://addons.mozilla.org/en-US/firefox/addon/distill-web-monitor-ff/