Do you foresee CALEA being successfully imposed on open source software (e.g. firefox) where users connect directly to each other without an intermediate server?
They do use some pretty bullshit stretching to count e.g. Skype as "interconnected" even though only a tiny minority of calls touch SkypeOut/PSTN.
I'm curious how this works if you have a disinterested third party running the interconnect; e.g. if I took TeamSpeak and set up a SIP trunk, does that make all teamspeak "interconnected voice over ip"?
I think some new "general purpose centralized voip" CALEA interpretation is the next most likely. I wouldn't be surprised if that happened already in some cases, at least semi-officially. ("it would be a shame if we had to seize a bunch of your servers every time we have a subpoena, you should just give us a nice UI and we'll even pay you per use...")
Going after pure peer to peer stuff is hardest. Commercial software would be easier, obviously, than open source, since you could apply some commercial levers/threats.