What kind of people are startups (and big companies) hiring?

I see job posts for Rails, Django, iPhone, Python, Javascript, and User Interface developers, many on YCombinator. I am especially interested in finding out what kind of interns have been hired at your companies or colleges, but I'm pretty curious about full-timers, as well. What kind of people actually end up being hired? What did they do? Did they create a simple web app with an MVC framework? Did they create their own lisp dialect? Did they have very good grades? My biggest question, especially for an internship, is if creating a bunch of web apps using recent frameworks pretty good evidence of ability, or are interns and full-timers expected to have run their own very successful business for years (of course, in which case, they would likely not even look for a job)? I'm probably over-thinking this. :) I ask because it feels like the more I learn here on Hacker News and at college, the less I know anything. Thanks!