Various phone companies around the globe have resorted to blocking VOIP traffic that they detect being carried on their lines. Companies like Vonage have started to get a lot more press the past few years as the adoption rate of VoIP increases and both businesses and home users turn to Internet based phone. The benefits of VoIP are numerous, from lower costs to avoiding long distance carriers, and it's precisely those features that the phone companies don't like. Some countries actually have laws prohibiting VoIP in one form or another, but that isn't stopping it. Whether for good or bad, the phone companies are starting to fight. This is happening in Europe, Asia, South America and the Middle East. Soon, perhaps, even the U.S. and Canada. Though there are laws in the U.S. that prevent such a frontal tactic, the phone companies still aren't happy - and there are other ways to restrict it.
Is this good business or is this just the signs of a dying technology fighting to maintain a monopoly? POTS won't last forever - but its death rattle may be a lot louder than people originally expected.