Important part of the story:
|Twitter said it has no plans to remove tweets unless it receives a request from government officials, companies or another outside party that believes the message is illegal. No message will be removed until an internal review determines there is a legal problem,|
And what happens to Twitter if they receive a request and then make a mistake in evaluating it's legality?
2012 could end up being a year of major censorship / restrictions / take-downs, etc., on the net.