This is definitely interesting. I'm currently working at a startup, but it's always good to see how others work too. Is this specific to developers, or can business side folks attend too?
This particular event is mainly for programmers. We're hosting this at YC itself, and we can't fit as many people as you could in an auditorium. But ultimately it depends on the presenting companies:
This is an interesting filtering process. Presumably, there will be some who attend this event already identified (based on their resumes) as desirable candidates for one or more companies.
Will this be asynchronous knowledge or will the attendees and companies have contact and/or show interest in advance?
The companies reading the resumes will be able to contact the people submitting them if the people submitting them say they can. There's a field for specifying that on the resume.