This is one of my biggest issues with a lot of the projects being posted lately - they look great but I don't know the tech stack until I finally look at the code. Would be great if people at least mention if their project requires node.js, ruby or what not on their homepage.
(I work at Deployd) From our perspective, one of our ultimate goals is to create a platform where the tech stack doesn't matter to the user. We've partially solved this with the Mac/Windows installer - it installs Node.js and MongoDB dependencies itself. That way, you don't need to know the stack unless you're developing extensions (which are node modules).
However, I do agree that we need to document the stack better for those that want to install from source, or host it themselves.
Shouldn't this be displayed on the homepage somewhere?