Web REST Call
The Web REST call event gives you the capability to fire an alert to any service or program that has the ability to receive REST calls.
When you create a Web REST alert event for the first time, you'll notice that there's a "place-holder" example already in place:
You'll need to have the specific address for whatever service or program you're wanting to fire the alert through here. *Most* services will have some sort of documentation on where to find this address, and what needs to be included in the body (i.e.: a security token) in order for things to work.