One way to think about webhooks is it's a way for me to respond to events that happen on another application.

For example, let's say I had a service that I follow my favorite artists, and that service had webhooks. Let's call this service M

Additionally I have my own service (like a wordpress site).

What I could then do, is set up a hook on M, that will send a message to my service and then respond to it in some way.