Which of the following best describes Real Time Bidding (RTB)?

Real Time Bidding (RTB) is best described as a real-time system for buying ad inventory. It enables advertisers to bid for ad spaces in a dynamic environment where impressions are bought and sold in the milliseconds it takes for a webpage to load. This system allows for highly targeted advertising, as bids can be customized based on numerous factors such as user behavior, demographics, and context at the moment of the impression.

In RTB, each impression is auctioned off to the highest bidder in real time, making it distinct from traditional ad purchasing methods that often involve pre-negotiated terms and static pricing. This model allows for greater flexibility and efficiency in ad purchases, aligning spending with the perceived value of each individual impression based on current data and analytics.

The other options do not accurately reflect the dynamic nature of RTB. A static approach to ad purchases implies a fixed methodology that does not adapt to real-time data, which contrasts with RTB's core function. A method for optimizing organic search results pertains to Search Engine Optimization (SEO), unrelated to the buying and selling of ad inventory. Enhancing brand visibility is a marketing goal but does not specifically capture the operational specifics of how ads are purchased and managed in real time through RTB.