said by KrK :

This was done purely as an anti-competitive move, not a "manage the network" move. Bell Sympatico chose to implement throttling on their customers some time ago. As a direct result, customers began leaving in droves for third party ISP's like TekSavvy. There has been much concern at Bell Sympatico about the losses of direct subscribers (they still make a healthy profit off the 3rd party ISP's customers, but naturally they make a much bigger piece when the customer is directly a Bell Sympatico user.)

Thus this new policy is born. Throttle everyone at the local level, therefore the third party ISP's cannot compete on the grounds they have an unthrottled network, since Bell Sympatico is doing it to them by force. Result they can stem their own customer losses because now there's little reason to switch.... Except for purely moral grounds.