If This Then That (IFTTT) provides an interface to chain events. Events can be data coming into the system or a certain schedule that has been fired or any such activity. Using an applet, one can chain various events to perform automation.
For instance, if movement is detected in the hallway then turn on the lights: a simple If This Then That scenario.
The IFTTT service can be used for non-IoT activities as well. You can read more about IFTTT here: https://ifttt.com/discover.