The pipe ( | ) of the internet generation (apparently).
Interesting blog post about exactly this : http://blog.iron.io/2013/09/7-reasons-webhooks-are-magic.html
I’m also quite excited about it, especially with systems like Drupal embracing the everything is an API approach (D8 https://drupal.org/community-initiatives/drupal-core#wscci).
Also seems someone tried to get it working for D7. https://drupal.org/project/rules_web_hooks