Monitor an entire web page -- or just certain areas/elements. The latter is helpful if the page has a lot of dynamic content, but you only want to be notified if a specific text box changes. (For example, a company homepage may have a new blog post every day, while new jobs may only show up once every few weeks. Instead of monitoring the entire page, which would trigger daily alerts of the blog post changes, you can set it to only look at a specific area of the page -- such as the job feed box.)
You get to choose the frequency that it checks for changes -- from every 5 seconds to every 30 days.
And there are different types of alert notifications to choose from (email, browser alerts, etc).