Don't be discouraged by that. :) We haven't gotten many applications yet and we don't care who you know, if you have a bunch of followers, or if you contribute to open source. (Personally I'm a bit bearish on GitHub as a resume - my publicly-visible GitHub is very underwhelming.)
Our selection process is pretty much: have you (or do you aspire to) build cool, interesting things and do you seem like someone we'd enjoy living with for 10 days (we do a 15min phone screen).
