Open Graph is the meta-tag protocol developed by Facebook in 2010 for controlling how a page appears when shared on social media. The tags live in the <head> with the prefix og: — og:title, og:description, og:image, og:url, og:type. Twitter has its own twitter:* variants for additional control; LinkedIn, Slack, Discord, and most major social platforms read Open Graph tags directly.
A complete Open Graph implementation has: og:title (under 60 chars), og:description (140-160 chars), og:image (1200×630 recommended), og:url (canonical URL), og:type (website / article / product), and twitter:card (summary_large_image for most use cases). The image is the highest-leverage field — social shares with a strong image lift CTR 2-4x over text-only shares.
For AEO, Open Graph is not directly a citation signal but contributes to the page's overall structured-metadata posture. Pages with complete Open Graph + schema.org markup signal editorial maturity, which AI engines weigh as a quality signal.
The most common failure mode is hardcoding the same og:image across every page of a site. Each canonical URL should have its own purpose-built OG image — generated dynamically or curated per template — for maximum social CTR.