LifetimeCommissions.com is a directory of affiliate programs that pay lifetime commissions or residual commissions for life.
The customer you refer to the merchant is "yours" for life.
An affiliate program paying lifetime commissions pays you every time the customer buys something from the merchant, not just for the first purchase.
An affiliate program paying residual commissions for life pays commissions on all recurring fees, such as monthly web hosting fees or auto responder fees.
If the affiliate program you join doesn't pay lifetime commissions or residual commissions for life, you're missing out on earning lots of money.