什么是Dark social？
Sharing that analytics cannot attribute: links passed through chat apps, email, and DMs arrive with no referrer and look like direct traffic.
Dark social is link sharing that happens in private channels analytics cannot see into: WhatsApp and Slack messages, DMs, texts, and personal emails. Clicks from these arrive with no referrer, so they are lumped into direct traffic even though a real recommendation drove them.
It is usually a much bigger share of sharing than the visible kind. Public social posts are the minority; most people share links one-to-one. The tell is direct traffic landing on deep URLs: almost nobody types a long article path by hand, so direct visits to /blog/some-long-post-title are nearly all dark social. Some teams estimate it exactly that way, treating direct visits to non-homepage URLs as shared links.
You cannot fully measure dark social, but you can recover some of it: put UTM-tagged share links behind your share buttons, use short links with tracking for content you expect to be passed around, and read deep-URL direct traffic as the word-of-mouth signal it is rather than noise.