Explain how RTB (real-time bidding) works.

Real-time bidding (RTB) is a crucial component of programmatic advertising that facilitates the automated purchase and sale of ad impressions in real time. This process occurs within milliseconds as a user loads a webpage or an app, allowing advertisers to compete for ad space dynamically. When a user visits a site, the ad impression is put up for auction, and multiple advertisers can place bids on it based on their targeting criteria, budget, and other factors.

The automation aspect of RTB is key; it streamlines the buying and selling process by eliminating the need for manual negotiations and contracts in advance. Instead, it operates through algorithms and data analysis, where each bidder can adjust their bidding strategy based on the performance metrics of past campaigns and real-time data.

The other choices do not accurately capture the essence of RTB. Manual bidding on advertisements suggests a level of manual involvement that contradicts the automated nature of RTB. Requiring prior agreements for ad placements would limit the flexibility and immediacy that RTB provides since the auction format inherently allows for bids on the fly without pre-negotiations. Lastly, the idea that RTB operates only during specific time slots is misleading, as the auctions can occur anytime impressions are available, making it flexible and always on