Why is it a big deal when OnLive already existed? Because it's being done by a major console company that has been in the market for about two decades now. That means a potentially massive library of titles some people might have never had their hands on and that you could never get unless you had the Sony platform it was released on. It certainly sounds great for people who didn't have a PS3 and want to play the games without going out and buying an older piece of hardware for a couple hundred dollars. Also being able to do so on typically non-gaming hardware could turn out to be awesome.
As far as the questions for why people are making a big deal about something talked about almost a year ago the answer is simple. Back then it was just an idea. Even up until now people would talk about it from time to time but you always got the feeling that it was something so far off that it may never actually happen. That it was just talk. Now it's being shown off. People can actually talk about how it works right now. We have a more specific timeframe to look forward to. In other words....
