Social proof is a big part of why kickstarter works. The startup pages should prominently display something like "X people have committed $Y".
Discoverability is also key. It should be easy to find your users, but I can only find you.
If you haven't implemented the above because you don't have any content, that's also a big problem. If you don't seed a site like this with content (from friends, family, cold calls, whatever) it causes all kinds of problems. For one, it makes it harder to see what the site does, because content is what happens when the site is doing things. It's also really unappealing at a basic human level, like an empty room. There's not much to look at, and you want to leave.
Your users' potential users don't want to "Validate this startup!". Your copy and design should align more with their needs.
The "Pledge" buttons are broken.
Your branding must be much weaker on pages like http://upstartly.com/startups/view/1. I would move all upstartly-specific content to the footer.
Hope that helps!