I don't really like to take traffic away from a site but that is horribly designed. I could only scroll with PGUP/DN due to the stupid control bar to the right.
Sorry to interrupt the bitching about the UI of the website, but...
I would nominate a working familiarity with:
Non-trivial graph algorithms
Serious distributed systems design (ie. building something where anything and everything can fail at any time, possibly in nasty or even byzantine fashion)
Formal methods
Optimization methods (ILP and so on)
Binary decision diagrams
as some other "ninja arts" if we're going to have to use the term "ninja".
I've never seen a worse layout for mobile viewing. Viewing on my iPhone reduces the content div to a mini scrolling box that immediately had me close the page.