RTB advertising transparency refers to the level of openness and clarity in the process of real-time bidding (RTB) for online advertising. It involves the disclosure of all relevant information and data, such as ad placement, pricing, and targeting, to both advertisers and publishers. This allows for a fair and competitive marketplace where all parties have a clear understanding of how their ads are being bought and sold. RTB advertising transparency is crucial for building trust and ensuring the effectiveness of online advertising campaigns.