As I expected, the development of Boost.Process has taught me multiple new things. First of all, I wanted to get familiar with the Win32 API because I knew nothing about it. I have achieved this objective by learning the details about process and file management and making Boost.Process work under this platform. Sincerely, Win32 is overly complex but has some interesting features.
Secondly, I have got a lot more fluent with C++ templates and have learned some curious coding techniques that I never thought about in the past. The most impressive one in my opinion is that templates can be used to achieve build time specialization, avoiding expensive virtual tables at run time and inheritance when these are not really needed. (I only considered them for polimorphic containers before.)
At last, I have also got into several utilities used for Boost development. Among them are Quickbook for easy document writing, Boost.Build v2 for portable software building and the Boost Unit Test library for painlessly creating automated test suites.
All in all I'm happy with the outcome of the project and the new knowledge. If SoC happens again, you should really consider joining if you have the chance!