You know the OGRE kickstarter added like 300,000 USD in the last 48 hours, right? These things have a way of getting posted all over (just as you're doing) in the last 48 hours and people on the fence swing by and pony up, it's actually pretty amazing. Also, occasionally they get a mention on Penny Arcade, and that seems worth between 50k and 150k worth of pledges all by themselves.
It helped Ogre a lot, that the tier where you actually got the game was 100 dollars. It has notably less backers than SpaceVenture.
Well, if you're selling a "huge box of stuff" you can't hand it out for 15 USD. OGRE is also kind of a bad example in retrospect, given the way SJG did his swag stuff, you donated extra to essentially buy extra tshirts and stuff, a lot of people came back last minute and some nearly doubled their pledges (but, really, how COULD I turn down a polo shirt with an OGRE embroidered on it???).