The problem with most classified software i have ever try is lack of duplicate content filter. Duplicate post will make your site looks spammy and bad for SEO.
I suggest classibase add duplicate ad filter feature: – users with same email unable to post the same ad post and add notification to extend their ad (to get on top listing page). – dealer can not post the same post, only unique post can be submitted. To get on top listing page they have to update their ad when expired. This will increase engagement and recurring visitor.
You can use PHP similar_text function to compare two string duplicate or not.