Blynk is a Platform with iOS and Android apps to control Arduino, Raspberry Pi and the likes over the Internet.
It's a digital dashboard where you can build a graphic interface for your project by simply dragging and dropping widgets.
It's really simple to set everything up and you'll start tinkering in less than 5 mins.
Blynk is not tied to some specific board or shield. Instead, it's supporting hardware of your choice. Whether your Arduino or Raspberry Pi is linked to the Internet over Wi-Fi, Ethernet or this new ESP8266 chip, Blynk will get you online and ready for the Internet Of Your Things.