IFTTT

IFTTT (IF This Then That)  is a free web-based service that people use to create chains of simple conditional statements, called  applets, which will coordinate small tasks between Internet and web services. For exemple, changes that occur within other web services such as Gmail, Facebook, Instagram, or Pinterest can be detected to decide an action. An applet may send an e-mail message if the user tweets using a hashtag or to copy a photo on Facebook to a user's archive if someone tags a user in a photo. Most of the suggested recipes work well without modifications, though some can be modified to match the requirements. Creating recipes is basically a point-and-click affair, and is thus simple and straightforward: It allows ample room for customization.

IFTTT employs the following concepts:
 * Services are the "basic building blocks of IFTTT". They mainly describe a series of data from a certain web service such as YouTube or eBay. Services can also describe actions controlled with certain APIs, like SMS. Sometimes, they can represent information in terms of weather or stocks. Each service has a particular set of triggers and actions.
 * Triggers are the "this" part of an applet. They are the items that "trigger" the action. For example, from an RSS feed, you can receive a notification based on a keyword or phrase.
 * Actions are the "that" part of an applet. They are the output that results from the input of the trigger.
 * Repices are the predicates made from Triggers and Actions. For example, if you "like" a picture in Instagram (trigger), an IFTTT app can send the photo to your Dropbox account (action).

IFTTT is thus a interesting feature that we can use in the case of IoT: we can use a sensor as a trigger, when the value is in a certain range then send a message, post a tweet or even post something on facebook.
 * Ingredients are basic data available from a trigger. For example, from the email trigger we can use subject, body, attachment, received date, and sender’s address.

Source
https://www.verizonwireless.com/archive/mobile-living/tech-smarts/what-is-ifttt-how-to-use-if-this-then-that/

https://en.wikipedia.org/wiki/IFTTT

http://www.webopedia.com/TERM/I/ifttt.html

http://www.digitaltrends.com/cool-tech/what-is-ifttt-and-how-does-it-work/