Sounds like a great scam... they can screw people on BOTH sides and make money! They advertise for engineers to work on projects in their "spare time" on projects brought in by people without the skills to do it themselves. This "company" makes the connection between people with skills and people with ideas.
I have to admit, it's a good idea if it was done correctly, but the potential for abuse is too great... patentable ideas, when they come along, could be all too easily swiped. It also looks like the engineers don't get paid unless the product goes to market, which is hardly ever for ideas not coming from big companies or their spin-offs.