The referral program is for owners to refer others to take a look at/try out one of the properties in the vacationclub system. Depending on location, this can be a stay of 2-5 nights at a very discounted rate with the condition that you have to attend a sales presentation for the program. You also usually have the option to extend the stay at a discounted rate.
Offers and properties vary and depend on demand and time of year (obviously you can't get in to a ultra-peak place during spring break) but they usually have a good list.