VoIP providers might have to pay telco operators, that own the last-mile to the home, to ensure quailty of service for their customers. I believe such a thing will not happen in places where there's enough competition on the last-mile, it would definitely make me switch to another provider... Many have feared something like this, but SBC in the US appears to be the first to actually make a move in the wrong direction.
"Sounds like the first step towards degrading VoIP calls. What SBC could do is assign VoIP calls that don't pay for TipTop a low priority, degrading the quality, but they would ensure QoS for TipTop. This might force quality VoIP companies to pay in for the 'voluntary' service. The volunteer is anyone who doesn't take one step backwards"