A banner exchange is a cooperative advertising network where website owners agree to display advertisements for other members in exchange for having their own ads shown on other sites. A is the underlying software that manages this process. It handles member registrations, tracks "impressions" (how many times an ad is seen), manages "click-through rates" (CTR), and ensures that the ratio of ads shown is fair based on the participation of each member.
The word "nulled" comes from "nullified." In software terms, it refers to a legitimate, commercial script that has been modified by a third party (usually hackers or crackers) to remove its copy protection and licensing requirements. Banner Exchange Script Nulled Definition