When I hit the "associate account" button on SF, it immediately gave me 100 rep and said something about it being for associating with my ubuntu.stackexchange.com account. How does this work, and why does it only seem to exist for certain pages? It didn't happen with any of my other 4 accounts when I associated them.
When you associated you other accounts before you had achieved 200 rep on Ubuntu? If so you wouldn't get the association bonus.
Oh, and welcome to serverfault. :)