Being as tall as I am its a funny thing when you meet someone who is near your height. At 6"7 that happens rarely, but when it does the outcome goes one of two ways. The first - and less common - is that you make eye contact, direct or indirect, and kind of give the other dude a nod. Like this scene from the office, but instead of black people, its tall people.
You're saying, "Hey Bro. Respect. You're tall, and I'm tall. Fuck Yeah!"
The second reaction, which is much more common; both parties snap their spine up and walk by looking at each other indirectly so as to gauge who is taller. Being the tallest person in sight is a competition, so when someone threatens your position as the alpha, you have to be sure who is the tallest. Upon acknowledgment that one is taller the other must bow down and give way to the taller. If, on occassion, you run into a situation where you can't tell there is protocol. You must immediately fight to the death in typical tall guy fashion.