How would we verify them, though?
Get them to write their username on their forearm and hold a sign with their username on it up by their head hair. Skin tone and hair analysis can be used to determine their posting privileges. Ass cheek skin might be better for skin analysis as there would be less chance of sunlight exposure complicating the results. Cultural tastes could also be screened for, to weed out undesirable influences. The posting privilege system could be ordered something like this, in descending order:
Caucasian
East
1, South East and Central Asian
South Asian
2Latino
Arab
3Afro-Caribbean
3Aborigine
4Ginger (Male only. Red-headed females are fully classifiable as Caucasian)
Unfortunately no system is perfect, nor immune to fraud.
1) Excluding North Korea.
2) Why is South Asia rank lower then the rest of Asia? Call centres.
3) Ebola vs ISIS. Difficult to call; subject to change.
4) Probably redundant as they couldn't invent the wheel let alone use the internet.