As you know you can see everyone who's registered for the conference, but I highlight 4-6 participants every day as this may be an easier way for you to digest the list. You can also look at the Program so see who is doing what.
Jean-Claude Bradley is a professor of Chemistry at Drexel University. He runs the Open Notebook Science wiki for his lab, blogs on Useful Chemistry and tweets. He is one of two people who will not just attend for the fourth time, but also present for the fourth time. At the next conference, Jean-Claude will give an Ignite-style talk "Games in Open Science Education", and co-moderate the session on Open Notebook Science. You can also read the interview with Jean-Claude from last year.
Kevin Zelnio is a researcher at the Marine Conservation Molecular Facility at Duke University's Marine Lab. He blogs on The Other 95%, on Deep Sea News and on The Online Laboratory of Kevin Zelnio and he tweets. I interviewed Kevin a couple of years ago. At the conference, Kevin will co-moderate the session on Broader Impact Done Right and do a demo of Darwin and the Adventure - The (i)Movie.
Steven Koch is a professor of physics at the University of New Mexico's Center for High Technology Materials. He blogs and tweets. At the conference, Steve will co-moderate the session on Open Notebook Science.