According to today news MSN and Yahoo agreed to help Chinese government in censorship and fight versus "politically sensitive" bloggers. The help consists in giving all of blogger's private data to the government on its request. Just like that. Now, if those big companies are so willing to give data away to Chinese government, do you think that they have a problem giving same kind of data to any "democratic" government - even more so, if somebody mentions terrorism threat. Not to mention that MSN and Yahoo are huge companies. Smaller companies are probably even worse in this regard. Heck, even European Union is sending a lot of private data to US when an European citizen flies over there. Privacy? What' that? We should sacrify all of our privacy for bigger goals, right? NO! Perhaps John Connor was right in the Terminator 3 movie - he lived practically outside the system.
So, think twice and one more time before you give any personal data to any company.