The problem is, as you reverse-engineer Skype and release source code that is meant to be liberally licensed, it still could be that the code would be practically unusable, due to possible legal issues.
IANAL, but from my understanding of the law, this is even a gray area in Russia (local RE laws restrict on what you can do with the obtained knowledge, and the law's wording feels pretty vague to me), and even if legal here, an US or EU court may have a different idea.
Maybe that's not true and I'm just over-cautious, but... well... there's clean-room reverse engineering (where one engineer analyzes the product and writes comprehensive documentation suite and another, completely unrelated person, reads the documentation and writes actual code) for a reason.