Gizmodo discovered Sony's PlayStation Move technology cannot support four players in its full configuration. The company revealed you can connect four PlayStation Move Controllers to a PS3, but it's impossible to use the PlayStation Move sub-controllers at the same time. If you want to use both controllers simultaneously to get the full Move experience, you're limited to two players.
So we contacted the company, and they clarified:
Four PlayStation Move controllers can connect to a PS3 at one time (or two PlayStation Move Controllers and 2 PlayStation Move sub-controllers).
So the total is actually quite a bit less than seven.
Does this mean that four players can't enjoy PlayStation Move titles at once? Absolutely not. Each player could use a single Move controller, much like some Wii titles need only the Wiimote. However, it does mean that designers are severely limited in what they can offer.