Basically it involves the concepts of Channels, Triggers, Actions, and Ingredients. And then you can make your own Recipes, suitably combining triggers and actions to your taste...
TechCrunch highlights the potential of the service, given Android's supported access to OS functions, in an article that is more than worth five minutes of your time, I would suggest.
Matthew Panzarino writes:
The major Android-specific channels include ‘Device’, which allows access to triggers based on connecting or disconnecting from WiFi networks and actions like setting wallpaper or ringer volume based on those conditions. There are also location, notification, phone call, photo and SMS channels, each with their own set of OS tendrils and possibilities.
Sending a text to your wife when you leave work, for instance, allows you to attach your name directly to a text to a loved one, rather than from an impersonal service. Here’s an interesting one that turns all of your Phillips Hue lights into Red Alert mode when you miss a call, and another one that appeals to me that sends an SMS back to a person leaving a voicemail letting them know you don’t check your inbox.
See also: The power of IFTTT, now on Android [IFTTT blog]