Hi. My name is Sadayuki "Sada" Furuhashi. I am the author of the MessagePack serialization format as well as its implementation in C/C++/Ruby.
Recently, MessagePack made it to the front page of Hacker News with this blog entry by Olaf, the creator of the Facebook game ZeroPilot. In the comment thread, there were several criticisms for the blog post as well as MessagePack itself, and I thought this was a good opportunity for me to address the questions and share my thoughts.
To the best of my understanding, roughly speaking, the criticisms fell into the following two categories.