Have you looked through their forums yet? I've already seen over 10 threads related to backers failing to get Ghost running on their shared hosting. John mentioned it would be built on Node.js when he launched the Kickstarter, but never actually explained what that meant, leaving hundreds of backers disappointed in the end.
Personally, I think it was a huge mistake. The whole point of Ghost was sticking back to a focus on simple blogging, and if there's anywhere people are going to host a simple personal blog, it's on the cheapest hosting out there: shared hosting. We both already see that with WordPress even though you could have that running on a VPS or Dedicated server, and even though it's now used more as a CMS for small and large businesses.
I posted about this a while back in fact:http://ibaku.wordpress.com/2013/05/08/good-luck-finding-cheap-hosting-for-your-ghost-blog/