Product releases are good. It helps you keep the momentum going and get real usage & feedback. In that regards, SharePoint webhooks is now Generally Available (GA) in Office 365!
This is a big step for SharePoint development as it introduces a lightweight HTTP callback system to receive notifications on specific events that occur in SharePoint. Today webhooks is available for SharePoint list items and it will be expanding to other SharePoint items as the platform matures.
Call to action:
If you are interested in the documentation, then head over here.
If you are interested in a hands-on tutorial, then head over here.
If you are interested in a reference implementation, then head over here.
This is just the beginning of many more to come!