I'm developing an ad-rotator system, in which the user has 4 levels of ads:
- Bronze: displaying ratio is 5%
- Silver: 25%
- Gold: 50%
- Platinum: 75%
So, a "gold" ad will have a better chance to be displayed than that of "silver" ones, and so on.
I'm not very good at mechanism, so would highly appreciate if someone could give me a hint on how to do it
Thanks in advance!