Signing up automatically gives you access to run on the simulator. For select users, we are providing some limited access to one of our prototype quantum processors. It's the one discussed in this paper [0]. This initial access doesn't allow a user to run full quantum programs like on the simulator, but but one can test out a few interesting experiments. You can read about what experiments are available here [1]. If you'd like to apply to run some experiments on our hardware then email us with some information about you and your interests at support@rigetti.com

The access to quantum hardware is limited at this point, but we'll be adding new features over the coming months.

[0] http://www.rigetti.com/papers/Demonstration_of_Universal_Par... [1] http://pyquil.readthedocs.io/en/latest/qpu.html