Just be careful while your disparately looking for any type of beta key from "official giveaways", cuz chances are they are not. I wondered why only 4,000 people liked that impostor page, they were just like me and hopefully not many more people.
Some obvious and some not, to the differences and the ability to see what is real and what is not. Make sure it is real. I derped so you don't have to. If you really want a key, just sign up at counterstrike.net and fill out the real, short, official, survey and wait. Pray to Gabe Newell, if it helps, but you know he wont answer.