What is it? Allows you to monitor changes to web pages
How is it of use to journalists? As a journalist you no doubt have a series of feeds set up to alert you to stories. For example, you may follow police appeals or new planning applications posted on a council website via RSS.
You might also be familiar with simple web scraping techniques which allow you to pull in an RSS feed or scrape HTML or XML into a Google Drive spreadsheet and then set up an alert so an email is sent to you when new information is added. (There's a guide on how to do this here.)
ChangeDetection.com provides another option. You add a URL and the tool will then send email alerts to notify you when text is changed on that page.
For example, I could set up a search for the journalism page on crowdfunding website Kickstarter. When a new project is added to the page I will then receive an email and can look to see if there is a story that is newsworthy for Journalism.co.uk.
ChangeDetection.com has a keyword option so you can only receive alerts if added or removed text contains a particular word.
The site, which was set up back in 1999, also allows you to alter the frequency at which you receive email alerts and select if you only wish to be notified if there is a major change to the page.