SayUncle has a video highlighting a new AR-15 trigger system. It looks to me like a semi-auto trigger, just one where the characteristics of the trigger change if you switch it to the fun setting. My guess is that the switch makes it a hair trigger, which is easier to fire faster. If you look at the video, it looks like the shooter is squeezing for each round fired.
I’m not sure why you wouldn’t just put a good trigger in your AR, though. The primary benefit, that I can see, is that it allow you to look all cool to the other dudes at the range by flipping your selector to the “auto” setting. The marketing seems to suggest this special trigger will make you a total high-speed, low drag, badass. Because of this, I expect it will sell well.