Basically, you help your friends or other new members or members of E2L earn lindens so you can make linden dollars for yourself too. As you may know, E2L offers a lot of ways for us to make money or get free lindens. They have Web Offers which is the most common way of making 50L$ to 200L$ in 5 minutes and SLBiz2Life that gives 100L$ per referral.
