GeN4 has a built in feature where members can rent un-referred users. They rent these users for a set duration of time, for a set amount of money, and have options like recycling them or renewing them when their set time is up . When these users view ads their upline receives a percent of the revenue. These options are set in the admin panel by the owner of the site. Packages of these un-referred users can be created to sell which will assist in generating revenue and will do the same for your members.
What bots do is take it a step further. They allow the creation of automated (non-real) members who behave as real members do. Their behavior is controlled by adjusting their click percentages and other options which changes how they earn. There are two versions of the bots. One clicks ads as in the physical since. The other does not. This is due to many requests for both versions being made and the many different business models which exist. You get both versions with purchase and are then able to decide on how you would like to use them.