This sounds like a neat event. For some reason, these types of events always attract a lot of students from MIT. I wish this type of involvement in the field of Open Source Hardware (OSHW) would happen at other colleges and universities. Hats off to the organizers.
I have no idea if any of those companies are doing open hardware. I have a hard time believing that they would, since they've built their empires on a completely different paradigm. However, both HP and IBM have embraced some open source software projects, so who knows!
it was somewhere close to 1000. I don't suspect that it was promoted on campus that much. They knew they were going to sell out tickets and they did pretty quickly. I think next year they'll have to have a much larger space and possibly go to two days.