Not off topic at all! I've seen those AIS beacons as well and think they have potential, but I'm not exactly sure how. I find that the problem with beacons of any sort (even a real EPIRB) is that SAR is usually delayed until they can be sure it is not a false alarm whereas a verbal declaration of MAYDAY always gets the ball rolling instantly.
A couple years ago I was the closest boat to an EPIRB that went off and instead of sending a chopper, or even calling out a MAYDAY the Canadian Coast guard called the vessel in question a couple times, then sent out a PAN PAN asking if anyone had seen it and if it really was in distress. I was able to answer and offer a little help, and it did turn out to be a false alarm. I did find this distressing though as a potential MOB. If you activate your EPIRB, PLB, or AIS ti will take a while for them to be sure it is actually a real event.
For me, I still favor the DSC VHF. Mostly because you can direct YOUR OWN BOAT back to you, but also so you can actually tell the CG that you really are a person in the water.
Another option that I currently employ is my submersible cell phone. I've had a Samsung Xplorer B-2100 for several years now and I've swam with it and accidentally fallen into the water with it as well. I keep my local Coast Guard's SAR phone number in my speed dial since the CG has discontinued the "Dial *CG" program. The phone has a spot for a lanyard and I tie it to my PFD when racing and have it on my person when cruising. It has 3-4 days of battery life and it has a separate button on the side that you can find by feel that activates a VERY bright LED flashlight. Once you have that light on your phone, you'll never be able to live without it.
Besides telephoning the USCG, you can also telephone the crew members left on your boat and direct the boat back to you, much as we were talking about with the VHF.
I reviewed it previously here:
cell phone for wet use?