In Augur v2, users can earn affiliate fees for referring new users to the exchange.
Referring new users with your unique affiliate link (found in the wallet dropdown in the upper right corner) will earn you a portion of their trading fees in perpetuity.
The fee paid to affiliates is specified during the market creation phase and paid to the account that referred the trader causing the transaction.
The referring address will be given 80% of the market specified affiliate fee and the remaining 20% is kicked back to the transaction sender. This split occurs to incentivize users to have and keep a referrer instead of attempting to avoid or take advantage of the system.