If This Then That is an incredibly impressive app that lets you create connections and commands for different apps on your phone and the web.
Tying it all together
IFTTT is based on "If this, then that" conditional statements found in computer coding and applied to your apps. In simpler terms, IFTTT allows you to mashup different programs together. For example, you can can program the app to have your post-exercise Fitbit activity saved to a Google Drive spreadsheet. It's also set up to work with GPS and the Internet of Things (IoT) so that you could have your house lights turn on as your near your home.
Each of these commands are called "recipes". IFTTT makes it incredibly easy to concoct a recipe by using a friendly visual interface and suggesting all sorts of popular apps to use including Gmail, Facebook, Instagram, Etsy, and many more.
There's also user-submitted recipes that are updated and provide a great way to discover new recipes. They are categorized into trending, all time, and featured. There's also "collections" which are themed such as recipes for music lovers.
Useful or unnecessary?
The idea of linking of programs or webpages using if this, then that statements is nothing new and has been done with Yahoo! Pipes. What separates IFTTT from the rest is its intuitive design and seamless social aspect. Admittedly, many of the recipes now are fairly niche (receive weekly email digests about Madonna's Instagram activity) but IFTTT is wisely looking to the futere.
IFTTT has lots of integration built in for IoT meaning that it's poising itself as the go to app for controlling your appliances. It also supports Google Glass with some recipes that send sports scores to your Glass. People who like to stay ahead of the curve with the latest tech should probably get acquainted with IFTTT.
A powerful app with lots of potential
At this point, IFTTT is a handy app that can make your life a bit more convenient. However, it (and apps like it) are very likely going to become more popular in the near future due to the Internet of Things which connects your phone to just about any object.