Content management systems are no doubt a pillar for the internet, empowering non programmers to build websites. However by their nature such CMS solutions tend to bring a ton of features that are not going to be used. Worse these features sometimes are even a hinderance when one needs to build something a bit more unique and custom. As such building a custom website with a CMS is a bit like being a stone mason working from a gigantic hunk of rock. The Symfony CMF proposes a different approach for such use cases.
Lukas makes regular appearances at conferences around the globe and has left an impression in various parts of the PHP community, not the least of which as co-release-manager for PHP 5.3 and launching wiki.php.net. He is also fairly known in database and search circles. Oh yeah and he plays a lot of ultimate frisbee :)