This document provides an overview of programmatic ad buying and real-time bidding (RTB). It defines programmatic ad buying as using software to automate the purchase of digital ads in real-time or otherwise, as opposed to traditional manual processes. It clarifies that while RTB refers to real-time auctions, programmatic buying also allows for guaranteed impressions. The document explains that programmatic technology makes ad buying more efficient and cheaper compared to traditional human-driven processes. It also provides examples of targeting tactics that can be used like audience, contextual, and site-based targeting.