I'm shocked that people think not letting others know their political actions is an issue of liberty or privacy. Would it be okay if your state representative didn't tell you how he/she voted on bills? Everyone in this thread is blathering about their political opinions on the internet, but put that opinion in a check box on a public government form and suddenly it's encroaching on your civil rights. If you are so insecure about who/what you vote for, don't vote. All political/government actions, aside from national security, need to have public transparency. Your vote is your participation and collaboration with the rest of our society; it IS a social, public form of communication.
Not only are peoples ideology blinding them to the true nature of this issue, but they are essentially advocating government corruption and identity theft. If your vote can't be traced back to you, then you can't be traced to your vote. The votes on your ballots could be changed, and since that ballot can't be traced back to you, someone just successfully stole your identity to rig an election. Congratulation, you have succeeded in hiding your vote, now truly no one knows what your vote was.
Grow up and be proud of your political opinion. Put your big boy pants on and participate in meaningful, finite, social discourse.