With 25 'friends' online, your 3rd degree network of contacts is estimated at 667,489. Global population might be 7 billion. 7,000,000,000 / 700,000 == 10,000.

With 25 'friends' online, your 3rd degree network of contacts is estimated at 667,489. Global population might be 7 billion. 7,000,000,000 / 700,000 == 10,000. I'm guessing 3 degrees was chosen because the NSA has enough targets to basically monitor anyone then.