[math-fun] Internet phone calls

I just read that Vonage has been enjoined from enrolling any new customers while a certain federal judge decides whether it is infringing on one or more patents held by Verizon for making phone calls over the internet. Can someone please describe just what these Verizon patents cover? (I ask because I've been able to have real-time audio conversations on the net for many years -- e.g., by being logged into the same Yahoo group as someone else at the same time.) --Dan