Email alerts are a great way to stay on top of what's new. You can be alerted of events like celebrity deaths, natural disasters, and political election and sports championship results with CNN breaking news alerts (bottom left under "My Alerts"). Google Alerts is another powerful free service that alerts you to recent news, blog posts, or videos on any topic you specify. You can use this to track the latest developments about a story in the news, a hobby you have, a celebrity, your favorite sports team, a specific company or an industry.
Montastic is a useful service that monitors websites you specify and alerts you if the site has gone down. There are free and paid versions of the service. Are you looking to monitor changes in specific webpages that aren't updated that often? ChangeDetection is your ticket for that one. It can even detect changes in certain parts of the webpage or disregard minor changes in it.