How do you know?

After playing around with the browser the question dawned on me, how do I actually know it is private? After all, its not like I can test it from the actual device I am using, right? Which brings be to the next set of questions, why are all the reviews positive? Not one single user has had a bad experience with this product? When the Bata came out, how many tested it and how many times was it broken?

vibratingegg about FREE Full Screen Private Browsing for iPhone & iPad, v4.4