I honestly don't see how you could use $1bil to legally disrupt Facebook, it just isn't enough money. Perhaps you could use that money to start another company

I honestly don't see how you could use $1bil to legally disrupt Facebook, it just isn't enough money. Perhaps you could use that money to start another company, not a competitor, and hopefully turn enough of a profit that one day you'll have enough money to either build a competitor or just buy Facebook? The only thing Zuckerberg cares about is his company, so unless you can threaten that you've got no leverage on him.