While I have great respect for Arduino, if you are looking to do something with networking, go buy a BeagleBone Black (or other cheap ARM linux board).
I was using a bit of hyperbole to illustrate the spectrum of choices. I think if you're building an internet toaster, you might want to reevaluate your priorities.
An internet connected microwave on the other hand... http://madebynathan.com/2013/07/10/raspberry-pi-powered-micr...