Re: Demonstrating aiki, demontrating aikido.Same thing ?
I disagree with Peter. I think one of the things O-Sensei did in creating Aikido was to eliminate a bunch of techniques and refine others so they all became vehicles for practicing and expressing aiki. Since this skill was passed on to the next generation only very spottily, much of what we see in Aikido has devolved back to jujitsu.
As to what aiki is, that's a big debate. For me, and I think my perspective is similar to that in the post referenced by the OP, aiki is the joining of the two kis of yin and yang at the point of contact to eliminate conflict. As O-Sensei said when asked by his students why they couldn't do what he did, "It's because you do not understand yin and yang."