At the moment, there is no fixed criteria really. If you are entrepreneurial and have started a company in the past I'd say you are welcome. If you have something to share that's going to be useful to other startups, you're welcome.
How about if you haven't done a startup, but are working on one more side projects with the potential to become actual startups. Something more than flipping Wordpress themes, more along the lines of the recently posted csspivot, gumroad, and others.