Honestly, the way it grows it doesn't make sense. What I'm thinking is that another pool is actually just a proxy for middlecoin. As the pool grows, it becomes larger, but gradually, and without big sudden changes because it's just a lot of smaller members joining. It would also explain the bumps in the history. They are HUGE if it was one persons setup, at one point half the hash power is gone. However, it makes sense if they lose a server link or type a line of code wrong...

Just a guess.