The info lovetoscrap gave is accurate. The DVC R/T board was never intended to be a free for all clearing house of DVC rentals, it was envisioned as a place where active, posting members of the DIS community could rent unused points or reservations to others members of the community.
Posting also creates a history that we encourage your potential customers to review. You can really get a feel for someones personality by reading posts they have made over a span of time.
Currently, we are allowing people to "catch up" to the 50 posts, but they still must spread them out over 7 to 10 days. However, beginning February 1st, we will only be checking the previous 6 months of posting activity for 50 non-Rent/Trade posts, and looking for a pattern of consistent activity spread over the course of those 6 months.
The DVC Moderators invite you to post your 50 non-Rent/Trade posts over the course of 7 to 10 days, and remain active by posting an average of 2 posts per week to maintain your ability to use our R/T Board.