Bluetooth 4.0 Low Energy profiles allow for easy connection to smartphones, tablets, etc. They can be used to control things and send data back and forth. The Apple requirements for Made For iOS do not apply either.
connectBlue makes some great modules for interfacing with Bluetooth 4.0 serial profiles
http://www.score-electronics.com/Score_ … nergy.html
It would be fantastic if Sparkfun would make a breakout board for this so we could easily integrate with Arduinos and iPhones.