1. There are two opposing theories about the NC rule:
A. No Contact is the best and quickest way to move on with your life and stop dwelling on past failure
B. No Contact is a form of reverse psychology to get your ex to regret dumping you and take you back
2. Yeah, No Contact applies to all forms of communication, even those not yet invented. No phone calls, no texts, no tweets, no Facebook shenanigans, nothing.
3. Either person or both can go No Contact. Maybe the dumper wants to forget the dumpee quickly. Or maybe the dumper wants to stay friends but the dumpee wants to move on.
I don't recommend going No Contact as a devious strategy to get the dumper back. The relationship failed for a reason, or possibly several reasons. Getting back together will eventually fail unless the underlying problems in the relationship are solved. And since those problems often have a basis in personality traits, deeply-held beliefs, or behavior learned as a child, it's unlikely those problems will get fixed in mere days or weeks or even months.