Acquisition channel
The broad bucket for how visitors arrived, such as organic search, paid search, email, referral, social, or direct.
See it
What it is
An acquisition channel is a broad bucket for how a visitor arrived: organic search, paid search, email, referral, social, or direct. It sits above source and medium. A visit labeled 'google / organic' has Google as its source, organic as its medium, and organic search as its acquisition channel. GA4 ships this ruleset as the default channel group and lets you define custom channel groups beside it.
Reach for channels when comparing traffic quality or deciding where to spend attention and money. The broad grouping makes a report readable, while the source, medium, and campaign fields remain available for drilling into a surprising row.
Gotcha: channel is a classification rule, not a fact carried by the visitor. Inconsistent UTM values create stray buckets, and direct is usually the fallback for traffic with no readable campaign or referrer. It includes typed URLs and bookmarks, but also links from apps, documents, and privacy tools that removed the evidence.
Ask AI for it
Build a BigQuery SQL view that normalizes visits into acquisition channels with one ordered CASE expression. Use utm_source, utm_medium, gclid, and document.referrer: classify paid search before organic search, then paid social, organic social, email, affiliate, referral, and direct only when no campaign or external referrer exists. Keep unmatched rows as 'other' instead of guessing. Return the mapping table, the SQL view, and tests for mixed case, missing UTMs, internal referrers, and conflicting gclid plus utm_medium values.