Controlling LED from web server I have a LED attached to my Arduino wifi shield that I want to control from my PHP web server.  In terms of communication, should I 


Make my Arduino a web server and then communicate with PHP web server via HTTP
Make my Arduino a web client and receive commands from my PHP web service.  I would parse the JSON response


Also my other question is should I communicate with JSON between my PHP web server or is there a better way to send commands to my LED light?
There's no need for either PHP or JSON. Simply detect when one of two URLs (say, /led/on and /led/off) has been accessed on the Arduino's web server, change the LED state, and return a 204 response.