Khalil Shreateh is an unemployed hacker in Palestine. But he's a "good" hacker who tries to help companies make their websites and software more secure, not a "bad" hacker who takes down websites or steals credit cards. Last week, he found a security hole in Facebook that let anyone post to anyone else's wall . . . even if they weren't Facebook friends with that person. Facebook offers people who find security problems at least $500 rewards, so Khalil let them know about the bug. But they ignored him. So he emailed again. And they ignored him again. So . . . he PROVED his bug by hacking Zuckerberg's WALL and leaving a post. He wrote, quote, "First, sorry for breaking your privacy and post[ing] to your wall, I had no other choice . . . after all the reports I sent to the Facebook team." Within MINUTES, Facebook fixed the bug and contacted Khalil. They apologized for not listening to him . . . then told him he won't get the reward for finding the bug because he'd violated Facebook's terms of service by posting on Zuckerberg's wall.