- Publishers (sellers) provide inventory, or the space where ads are displayed. This may be a website or a mobile app. For example, www.nytimes.com, www.cnn.com, and www.imdb.com are all publishers who sell ad space.
- Advertisers or marketers (buyers) purchase inventory for the display of advertisements. For example, Microsoft, Amazon, and Target are all advertisers.
- Ad networks serve as brokers between groups of publishers and groups of advertisers. Networks traditionally aggregate publishers and advertisers and also handle remnant inventory, but they can have a wide variety of business models and clients.
- Users are the target customers for advertisements.
- Data providers provide information useful for targeting. This can be contextual information about the web site or web page where the ad is displayed (for example, you wouldn't want to display a vacation ad next to a newspaper article about a plane crash), behavioral data about users, viewability data about advertisements, or other kinds of data.
- Data Management Platforms (DMPs) are centralized systems for gathering first-party data, integrating with third-party data, and applying this data to one's advertising strategy. A DMP may offer the following features: estimating the likely reach for a user segment, measuring the lift from using data, acting as a financial clearing house between data buyers and sellers, and assisting publishers in monetizing data on their users. DMPs most commonly work with user data but may also work with contextual data, or other types of data. For example, Sizmek and Rocket Fuel are large DMPs.
- Demand Side Platforms (DSPs) enable advertising clients to buy digital media on many different selling networks, exchanges, and platforms through a single interface. For example, AppNexus, ONE by AOL, Rocket Fuel, and Turn can act as DSPs.
Supply Side Platforms (SSPs) enable publishers to access demand from many different networks, exchanges, and platforms through a single interface. For example, AppNexus, Liverail, OpenX, and Pubmatic can act as SSPs.
- Rich media vendors create, serve and manage rich media advertising. Rich media refers generally to advertisements with audio, video, or other interactive elements.