At first, I thought it was pretty ballsy of them to open this all up, but then I realized that this isn't really where their competitive advantage lies. Plus, I think they probably felt that there was still plenty of room for improvement since it had just been a small team working on it (whereas I have a feeling that Google has a much larger team working on these things). In the end, the community wins by getting to see their designs, and Facebook wins by continuing to iterate on them as the community discussion leads to improvements.