Did Sony simply follow in Nintendo's footsteps and copy their motion-sensing idea while developing the SIXAXIS for the PS3? We don't know ... that's one argument that will probably never reach a conclusion. Has Sony copied Nintendo in the past? Definitely. Will they do it again? Most definitely.
If I could direct your attention to this page here.
An input device providing users with a pointing capability includes a sender portion and a receiver portion. The sender portion is adapted to be manipulated by a user to specify a target point within a target area. The sender portion projects a light beam including a pattern on to the target area. A receiver portion includes one or more sensor units located in or near the target area. At least some of the sensor units receive a portion of the light beam regardless of the location of the target point within the target area. A processing unit in the receiver portion analyzes the portions of the light beam received by one or more sensor units to determine an attribute of the target point. The attribute can be the location or relative motion of the target point. The receiver portion may be integrated with a display device.
Now, this could just be some sort of a media remote for the PS3. They did say there were firmware updates coming that would enhance the PS3's media capabilities. But then again, if you hit that link above, this is what the first few lines say:
A PS4 will be launched by Sony but not until at least 2010 claims the Vice President of Technology for Sony Computer Entertainment Europe, Paul Holman.
What will happen between then and now is that Sony will introduce a series of firmware upgrades that will give the PS3 more media centre capability while allowing for the introduction of third party applications and hardware "Such as interactive controllers" similar to the Nintendo Wii he said.
Way to be subtle, Sony. I can't wait to check back for the comments on this.