Digital display advertising involves placing graphical ads on websites, blogs, and other digital platforms. The ads can take the form of banners, interstitials, videos, or rich media.

Here’s how it works:

1. Advertisers create ads and choose their target audience based on factors such as location, age, gender, interests, behaviors, and more.
2. The ad platform uses algorithms to determine which websites and pages to show the ads on based on the target audience the advertiser has chosen.
3. The ads appear on the websites and pages that have been selected, and users can interact with the ads by clicking on them, or hovering over them to view more information.
4. Advertisers are charged based on the number of impressions (the number of times the ad was shown) or the number of clicks (the number of times the ad was clicked on) the ad received.

Pros of digital display advertising include:

1. Reach: Digital display advertising has the potential to reach a large and diverse audience, depending on the targeting options chosen by the advertiser.
2. Measurable results: Advertisers can track the performance of their ads and make data-driven decisions about their campaigns.
3. Cost-effective: Compared to traditional advertising, digital display advertising can be very cost-effective, especially when targeting a specific audience.
4. Brand building: Digital display advertising can help build brand awareness and recognition by repeatedly showing the ad to the target audience.

Cons of digital display advertising include:

1. Ad blindness: Users may become desensitized to display ads, especially if they see the same ad repeatedly, reducing the effectiveness of digital display advertising over time.
2. Ad blockers: Some users may use ad blockers, which can prevent them from seeing display ads, reducing the reach of the target audience.
3. Low engagement: Display ads may not receive as much engagement as other forms of digital advertising, such as social media ads, reducing the impact of the ad.
4. Ad fraud: Some digital display ads may be shown to bots, fake or low-quality traffic, instead of real human users, which can be difficult to detect and reduce the effectiveness of the ad.

Here are some of the main digital display advertising platforms:

1. Google Display Network (GDN): The Google Display Network is a network of over 2 million websites, videos, and apps that show ads through Google AdSense. Brands can create a variety of ad formats, including image, video, and rich media, that can appear in a variety of sizes and locations on websites and apps.
2. AdRoll: AdRoll is a cross-device retargeting platform that helps brands reach their target audience across multiple devices. AdRoll works with over 700 exchanges and DSPs to reach over 90% of global internet users.
3. Taboola: Taboola is a content discovery platform that helps brands reach their target audience through native and video ads on websites and mobile apps. Taboola works with over 200,000 websites and apps to reach over 1 billion unique users per month.
4. Outbrain: Outbrain is a content discovery platform that helps brands reach their target audience through native ads on websites and apps. Outbrain works with over 15,000 websites and apps to reach over 1 billion unique users per month.
5. Criteo: Criteo is a performance marketing platform that helps brands reach their target audience through display, video, and mobile ads. Criteo uses machine learning algorithms to predict which users are most likely to convert and reach those users across multiple devices.

These platforms allow brands to reach their target audience with highly targeted and personalized display ads. They also provide a range of targeting options, such as demographic, geographic, and behavioral targeting, to help brands reach their desired audience. Additionally, these platforms provide real-time reporting and analytics, allowing brands to track their campaign performance and optimize their advertising efforts.