Would Mark Shuttleworth use Gentoo had he not founded Ubuntu?
Fortunately, sping said almost everything there is to say about LinuxTag. But there’s one important part missing: We finally made a peace treaty with what many call Gentoo’s arch nemesis (no pun intended?): Ubuntu.
While Ubuntu lost the “just works on your notebook” unique selling point a while ago (thanks to freedesktop et. al.), we could convince Ubuntu founder Mark Shuttleworth to sign our Gentoo slogan “It’s all about choice” — so maybe in a year from now, you might see USE flags in Ubuntu as well. Don’t believe it? Here’s proof.
On a more serious note, I really like how events like LinuxTag encourage collaboration between distributions. You often meet people that do similar things in a different way, learn about new technology and ideas and (here’s the best part) most people will even want to show you how they integrated something and convince you to do it similarly. Try to get that with an i*hone at some consumer convention.
Oh, and if you read this whole text to get an answer to the question in the title: No. He was a Debian developer years before Gentoo was on the horizon.