As you probably guessed from the name TCP optimizer is going to change some TCP parameters during power the iPhone. This kind of change will affect the speed of network connection - which could be slightly increased - and in particular loading and visualizzione best video on YouTube, accessible via the native application of IOS.
TCP optimizer is compatible with all devices and requires iOS 3.1.2 or higher. The developer is not recommended for use on Apple TV second generation. To uninstall TCP optimizer you must first remove it via Cydia, and then do a restart iPhone to restore the original settings.