Can you see the irony? Serially, several large US telcos sued Vonage and as Daniel Beringer wrote at GigaOm. " Vonage lost because of the difficulty in finding the proper documentation of prior art 15 years after the fact." and concludes" A formal process of filing prior art to the public domain will protect an emerging infocom industry better than just depending on overworked patent examiners and applicants for prior art searches."
And after 15+ years those same big telcos are fighting for that IP to still not be made available to consumers. They have convinced Apple and Microsoft to not allow VoIP applications on cell networks – only via Wi-Fi. And even on Wi-Fi some carriers block VoIP packets.
I think patents should be awarded with a “use it or lose it” philosophy. Certainly be nice if courts sided against “defensive patents” – those selectively invoked to stifle competition.