Apparently some low-ranking district court judge now makes law.
Congratulations on one of the most backwards decisions in recent history.
"ip number gives it away" its misunderstandings like this that are causing all this hoopla. The IP address you are using at a given time will be used by someone else in the near future (in most cases). While the ISP can track you - assuming you do not use a proxy, or series of proxies, which everyone with a brain who posts hateful comments now will - they can only track it to your house. MAC addresses are easily spoofable.
Now, imagine you share your wireless network with three or four people - family, or friends. How do we establish who was posting?
Or, better yet - your wireless network is unsecured! Ooops! Anyone can now post using your IP. Checking the neighborhood, I see all kinds of default password and WEP-less open access networks. Good luck tracking down who is who.
I'm sorry, I have not read the comments and so cannot speak to their nature, however, no matter how bad they are, I don't think that this kind of disclosure is necessary - it will have a huge chilling effect. And the clever ones will still be able to say whatever they want, and innocents will get caught up in bizarre legal dramas because of both the courts and the defendants incomprehension of the underlying technology.
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I know everyone here knows this, I am cross posting from the Globe and Mail. Rarely have I been so outraged at a ridiculous and backwards court judgement.