It's been shown that birds have metal in their brain acting as a compass. So when the birdy wants to go home he just flys in the direction that feels right thanks to the metal in his brain.

So, what if you could hook electronics up to brain nerves? Or even if you couldn't connect directly to the nerve, you could implant a device that reacts when it receives a certain radio signal. It might give out an electric charge or just move a little bit. So anytime this signal would cross your path you could 'feel' it in your brain. Or it wouldn't even have to be in your brain, it could be in your foot or something.

Then you'd implant a device into your brain that would transmit a certain radio signal when there's activity in that part of the brain. For instance, if we see that there's activity in a certain area of the brain when a person is angry, then we could set up the device to transmit a certain signal when it detects activity there. So the transmitter would transmit the signal when you're angry, and then someone else's reciever would pick up the signal and they'd 'feel' it in their brain.

So technology advances, we minaturize all the electronics, learn more about brain activity, wire the whole brain, run some wires out the ear and change the batteries every couple of months. And there you go, two or more people can know read eacother's thoughts.

Possible?