It seems that I can't write this enough. Whatever happens on Facebook stays on Facebook. It's not the real world. Relationships that start, or worse, exist on that social networking site don't really exist in the flesh. I have known far too many people who freak out because of the profound disconnect between their Facebook relationship, and the one offline.
It's like the Matrix. The idyllic dreamworld run by robot octopi has nothing to do with the gritty, post-apocalypse where actual humans live.
That said, I have two answers for you. Some guys, who live in the Matrix, will think "Awesome!" when poked. And other guys will think "WTF is a poke?" Seriously, what is the point of "poking?" It's the one thing on Facebook I just don't get. Who pokes people IRL? If I was at a bar, and some woman came up behind me and poked me in the fat wings, I'd be all "Anti-win."
I mean, I get that "poking" is, like, flirting? For shy weirdos? Instead of poking... why not "like" something he wrote? Or send him a message that says "Hi. Would you like to breakout of your embryonic-fluid filled cyborg cocoon and then go explore the rocky tunnels beneath the surface of the scorched Earth?"