This summer is looking like an awesome period for new development features and the Office PnP team recently published a web cast on SharePoint Web Hooks in Office 365, although this is not yet released, the public preview for first release tenants will be due this summer.
So what are Web Hooks?
Web Hooks are an asynchronous push mechanism to provide notification to a remote endpoint for changes. In the context of SharePoint, this would be similar to Remote Event Receivers that trigger a remote call when changes are made to the subscribed resource i.e. lists or web.