In 2001 Harmonix released a game called FreQuency, it was their first major game and it recieved both critical acclaim and several awards. Two years later, FreQuency received a sequel called Amplitude. I only mention these earlier games because taking a quick look at the above video will show that there are currently only 65 likes and 355 dislikes, many of the commenters saying that Harmonix are trying to cash in on the success of another game similar to FreQuency and Amplitude called Audiosurf (released in 2008, for the sake of fairness).
Rather than ripping off Audiosurf, Harmonix are going back to their roots, offering an arcade-like title that anybody can pick up and play, while offering compatibility with the main Rock Band titles for massive fans. It's a win-win situation and, if you didn't see enough gameplay in the interview we posted earlier, the official announcement trailer above should keep you going for a few more minutes.
While details are few and far between at this point, it looks like there will be 20-25 brand new tracks (which will be instantly playable in Rock Band 3, with instruments) and an accompanying Facebook app to increase the social aspect of the game. We'll post further details as they're released but, for now, know that this is definitely one to watch.