20mbps up speed is essencial are you kidding? At 10mbps (approx) I have three people online at the same time.
1 playing on facebook 2 playing twitch-based video games online (twitch mechanics = it is important to know exactly where the other player is because you are avoiding his bullets or fireball or whatever, WoW is not twitch based, counterstrike is)
None of the 3 people experience anything less than perfect service, all running on the same router.