什么是Direct traffic？
Visits with no known source: the visitor typed the URL, used a bookmark, or came from a link whose referrer information was stripped.
Direct traffic is what analytics tools report when a visit arrives with no referrer and no UTM parameters. The optimistic reading is that these people typed your URL or used a bookmark, meaning they already knew you. The realistic reading is "source unknown."
In practice a large slice of direct traffic is misattributed. Clicks from native email clients, mobile apps, messaging tools, PDFs, and some HTTPS transitions all arrive referrer-less. This hidden sharing is called dark social, and on many sites it dwarfs genuine type-it-in traffic. A sudden spike in direct traffic usually means someone shared a link in a channel that strips referrers, not a surge of brand recall.
You cannot eliminate direct traffic, but you can shrink it: tag every link you publish in emails, social posts, and documents with UTMs, so only the truly unknowable remains.