The Facebook-originated meta-tag protocol that controls how a URL appears when shared on social platforms. Used by every major platform beyond just Facebook.
Open Graph in plain English
Open Graph (OG) tags are <meta> elements in the page <head> that specify how a shared URL should appear on Facebook, LinkedIn, Slack, Discord, iMessage, WhatsApp, and most other platforms that render link previews. The core tags: og:title (the headline shown in the preview), og:description (the secondary text), og:image (the preview thumbnail, ideally 1200x630px), og:url (the canonical URL), and og:type (article, product, website).
Without OG tags, social platforms attempt to extract title/description/image from your page heuristically. The results are inconsistent — they might pick your nav text as the title, an irrelevant inline image, or no image at all. Explicit OG tags give you control over the preview, which directly affects whether someone clicks through.
For ecommerce, OG tags should be set per-page: each product page has its own og:title (the product name), og:description (the value prop), og:image (the product photo at 1200x630), and og:type (product). Each blog post has its own. The homepage has its own. Setting OG tags globally to brand-level defaults wastes the most powerful per-page benefit.
Common mistakes: og:image too small (under 1200x630px gets rendered grainy or cropped), og:image hotlinked to a remote server that might be slow or fail (preview fails to load, link looks broken), og:url pointing at the page's URL with tracking parameters (the social shares accumulate against a different URL than your canonical), and missing og:image entirely (the link preview defaults to no image, which dramatically reduces click-through rate).
Why open graph matters for ecommerce
For ecommerce, every share of a product link is a potential conversion. A product link shared in iMessage with a beautiful product photo + clear title gets clicked; the same link with no preview gets ignored. The difference is 10x click-through. The OG tags are set-and-forget — once your product page template includes them, every product page automatically benefits. AI tools (ChatGPT, Claude with web) also read OG tags when summarizing links shared in conversations, so the same investment improves both social and AI representation simultaneously.