Given posets $P,Q\in M$, I would like to know under what circumstances there are mutually generic filters $G\subseteq P$ and $H\subseteq Q$ (generic over $M$). Also, what are the characterizations of mutual genericity? And finally, what can we say about the relation between $M[G]$ and $M[H]$ in that case?

I have a slight difficulty finding references to the notion and properties of mutual genericity (whatever they are).


Question: When cellphone providers give "unlimited social networking", how do they identify the traffic?
Answer: I would think that a combination of checking DNS queries and IP filters would be the easiest way.  The IP addresses for the allowed list of sites should be known.  I can't think of any reason they would need anything more advanced.