Display advertising covers the visual units that sit beside, above, or inside web content. Banners, rectangles, skyscrapers, interstitials, and video pre-rolls all fall under the label. They come in standard sizes so publishers and advertisers can trade them easily.

Buying has shifted from direct deals with individual sites to programmatic auctions that clear in milliseconds. That shift lowered costs and expanded reach, but it also made fraud and placement quality bigger concerns.

Standard ad sizes

• Leaderboard, 728 by 90 pixels
• Medium rectangle, 300 by 250 pixels
• Wide skyscraper, 160 by 600 pixels
• Mobile banner, 320 by 50 pixels

Click rates are low, often under one percent, but display remains useful for reach and retargeting. Judge it on the objective, not on clicks alone.