Join via: https://join.uphold.com/?kid=SP137
"Uphold Referral Program, where you and your friends can participate in the US$500K giveaway we’re offering to those who help us spread the word.
It works like this:
For every qualifying friend you refer, we’ll pay out US$20 ($10 to you and $10 to your referred friend);
AND if you refer multiple friends to Uphold, you could also win the grand prizes in the Referral Leaderboard competition (including the US$25K top prize!)."