I have heard several guild members living in Canada rececently complaining about their internet connection. Thought you might find this interesting.

http://massively.joystiq.com/2011/03/27/rogers-throttles-world-of-warcraft-across-canada/

It says if you turn off peer to peer transferring they will leave you alone. Not sure if that is accurate or not but I would try it :)

If you read the article, it says the only thing they claim they're filtering is the torrent-style update mechanism, i.e. the bit that downloads new updates for WoW. In theory, that shouldn't affect gameplay at all, as that goes over different ports. Then again, they didn't even mention filtering of the updates until it got pointed out, so who know.... They might be filtering the game packets too. And that *would* be asking for trouble.

Actually, it says they are slowing down/throttling the connection, and they are using the bit torrrent, skype, and other application criteria to determine WHO they are throttling. But it's not a filtering on the specific ports - it affects everything. That's why they say turning off peer to peer on the game will fix your game connection.