"Celebrities" was my first thought when I read that, too. It seems like the requirements are inverted from what I'd expect: the ability to use the STL effectively and to grok (some) Boost seems almost like basic C++ proficiency to me, while the open source requirements are just nonsense fluff. I'm not sure I understand how prolific contributions to open source projects translates into the ability to work with others or write quality code.

Also the pay seems a bit low. I make more than their top rate, and I'm not working on anything anybody would claim to be world-changing innovation, nor would I claim to be a C++ superstar. I was the first to introduce C++-11 to the very mature C++ codebase, though.