Siri, Apple's personal assistant built into iOS, can perform a number of tasks by simply using voice commands. It's a pretty capable service but there are many other commands that Siri simply can't perform due to its locked down nature.
A service called GoogolPlex, however, promises to unleash the power of Siri by simply changing your iPhone's proxy settings to use GoogolPlex's servers. Voice commands can then be used for all sorts of tasks from controlling Spotify and unlocking your car door to turning on the lights in your home and adjusting the temperature.
So, what's the catch? Basically, the hack boils down to a man-in-the-middle attack as you're sending all of your voice commands to GoogolPlex servers instead of Apple's servers. In addition to adding a little more time to the already slowish nature of Siri, this means that someone else is receiving your data.
The company only claims to receive voice commands that start with "GoogolPlex" to help keep your data private and prevent their servers from crashing. But even still, if privacy is a concern for you, then GoogolPlex probably isn't for you.
In the same regard, I suspect GoogolPlex won't be for anyone too much longer. Apple typically patches these kinds of workarounds and with iOS 8 just around the bend, it's probably a safe bet that it'll get locked down soon enough.