This project is a very basic tutorial using Blynk with Arduino and Ethernet shields.
Blynk An open IoT solution that allows you to control and monitor Arduino from your smartphone without creating a separate smartphone app. However, you should use Etherenet Shield for Arduino. Apart from Arduino, it can also be used in Raspberry or ESP-12.
This post kindly explained Blynk usage sequentially.
I think Blynk is the simplest solution to implement IoT.