While at NADA I had a few meetings and I got to see behind the curtain on human tracking, geofencing, IP address to real address association and how that data is being shared and sold between vendors. It's incredible. It's also incredibly scary. These guys know all your devices, all your shopping habits, where you live, where you work, what you drive and when you leave each location each day. They sell that data to other companies who are using it to target you with specific ads. I haven't seen a great example of someone using it in Automotive or general Marketing yet, but I've seen the potential.
As for iBeacons, the biggest hurdle is that the functionality is turned off by default on most phones and it requires an App. Works great for someone like AutoTrader with 100s of 1000s of app installations, but for your dealership you can't just toss popups and tracking onto their phone unless you're part of one of the massive beacon networks.
