This is one of the most important apps available. Using this, you can anonymize internet traffic at the expene of a little latency. I configure Firefox to run through Tor and Safari to run naked. If I am traveling or on an open network, I exclusively use tor for traffic I am concerned about (e.g. online banking and whatnot). You simply avoid man-in-the-middle attacks, phishing, sniffing and other gibbersh with Tor. You also are completely anonymous.