True, true. In which case it seems like Kickstarter is the one that may need to collect sales tax, not the ones taking advantage of the service they provide. Clearly we are in some murky territory with regards to defining the entities involved.
I think Kickstarter is in very murky waters. They assert that they do not take charity or investments, nor that they sell products. People pledge money to a project that they want to succeed. If the project is fully funded, and it succeeds, they may receive rewards for their pledges.
But the rewards are not guaranteed, and I think that this is the way they skirt sales tax. On the other hand, it almost seems like it's gambling on the success of the project, which would then sway into the territory of contests, gambling, betting, etc.
Either way, Kickstarter is making bank. 5% of all money that goes through their website goes to kickstarter, and it requires a very modest team and server costs to manage, so they are making money hand over fist there.
Eventually the state they reside in is going to want a cut of that action.