How do I know I won't get ripped off?

A big drawback of this type of funding is that, unlike buying a game in a store, investing in a community game involves "buying" something that doesn't exist yet.  Naturally, we want members to be sure that their contributions are going to result in an actual game.  The common concerns that we want to adress are:
 
What happens to my donation if the funding funding goals aren't met?
This is the reason that we are using a pledge system rather than asking for donations up front;  No one wants to donate to something that only might happen;  If the pledge goals aren't met, there is no loss to members since the pledges are non-binding.  And if the goals are met, members can donate with the confidence that there is enough support from other members to actually go forward with development.
 
But since pledges are non-binding, how do I know everyone else will fulfill their pledge?
Because there might be some concern about how many pledges will actually be fulfilled when the time comes, we will not be collecting contributions directly, but via escrow;  If a substantial portion of pledges go unfulfilled, those who did contribute will have their donations returned.
 
Even so, how do I know you guys will actually make the game once the funding is in place?
Before collecting any funds at all, the Metropolis Project will be incorporated as a registered non-profit controlled by the community (see the "Organization" section of the FAQ for details);  Our charter will establish our mission and specify how funds are to be used, and will be published on the website.  The project organizers are also happy to address any concerns or questions you might have, and can be contacted here.
 
For more detailed information see this article.