What does poking someone mean in facebook?

Poking isn't much of a big deal. It is merely sending a notice to their homepage that says:
"(insert your name) has poked you". Then the person you poked has the option to "poke back" or "Ignore".
It is just a cycle of random poking that shows up on the side of your homepage. I hope that explains it for you! :)

I think if a guy (if ur a girl) pokes u their flirting... :)

Absolutely nothing, theres no real purpose for it they just thought it would be cool