I'm new to the jailbreaking community with my iPad 2 and iPhone 4 both recently jailbroken. I'm curious on how the outside world views my jailbroken devices. I noticed the Optimum App doesn't work anymore because my iPad is jailbroken - does that mean that any outside company for which I attempt a download can determine my iPad is jailbroken? Can they also determine my name or Apple ID somehow, or is it just a blind analysis of my operating system that somehow shows Cydia is installed? Is it fair to assume that Apple knows my devices are jailbroken? I know it's legal, but perhaps they would be less helpful if it comes to service issues, etc. Likewise, if I delete an app and then re-download it, how does the developer know that I previously had it installed? For example, I downloaded the New York Post app awhile ago, then deleted it within a few days. When I redownloaded it recently, it told me my free 30-day subscription was over. Is there any way to completely clear out my iPad's cache or whatever so that an app can be cleanly re-installed with no trace of the former app? I'm curious from a technical standpoint what an outside company sees of my device when I download one of their apps and how they know what I've had on the device in the past.