Mårten Gustaf Mickos - formerly MySQL CEO and now open source strategist at Sun until the end of Sun’s fiiscal 3rd quarter 2009 - and Ulf Michael Videnius (aka Monty) - MySQL co-founder and CTO, now driving the development of Maria, the new storage engine Maria - both quit Sun Microsystems.
Mårten leaves Sun during company reorganization, apparently because frustrated by Sun bureaucracy, but reading excerpts from his staff e-mail it looks like if he is missing the challenge, and the freedom to choose.
Monty’s decision to quit his job at Sun comes from great technical controversy on the subject of MySQL 5.1 release and, probably more important, because Sun is not moving to open up server development as fast as he would have liked.
Buying a proprietary software company is easier, typical assets include people and all intellectual property with the code base. Integrating open source acquisitions is more complex, though.