The use of the word "scam" is really inaccurate based on the rest of the post. He agrees that the demo is real, and calls it a scam since others are working on similar things and they are trying to get funding. Neither others working on the same thing nor trying to get funding make something a scam. It would be a scam if they weren't really rendering what they say they are in real time, but Notch doesn't claim that.