David is from CVUT/Open Informatics - http://oi.fel.cvut.cz/en/home. I'm not sure about Tomas. I met him some time ago when they were working on a web app with David. These guys are really passionate about building things on the web, that's for sure :)

Would you mind getting in touch? My mail should be in my profile. It's always nice to meet people from HN in Prague :)