Glossary · Traffic sources & UTMs
What is channel grouping?
Channel grouping is the set of rules an analytics tool uses to sort every visit into a marketing channel — such as direct, organic search, paid search, social, email or referral — based on its referrer, UTM parameters and ad click ids.
Also called: Default channel group, Marketing channels
Updated
How does channel grouping work?
Each session is checked against an ordered list of rules; the first match wins. A typical sequence: no source at all → Direct; a paid medium (cpc, paid) or an ad click id with a search source → Paid Search; a known search engine referrer → Organic Search; a known social network → Social; utm_medium=email → Email; anything else with a referrer → Referral.
Google Analytics 4's default channel group has around 18 channels, including Organic Shopping, Organic Video, Paid Other, Audio, SMS and Mobile Push Notifications. Simpler tools use five or six.
Channel grouping example
| Landing URL / referrer | Channel |
|---|---|
| No referrer, no UTMs | Direct |
Referrer google.com, no tags | Organic search |
?gclid=… | Paid search |
Referrer t.co | Social (X) |
Referrer chatgpt.com | AI (or Referral in tools without an AI channel) |
?utm_medium=email&utm_source=newsletter | |
Referrer someblog.com | Referral |
Why channel grouping matters
Budgets are set per channel, so channel reports are how marketing gets judged. Rules that misclassify even 10% of visits — untagged ads counted as organic, newsletters counted as direct — lead to moving money in the wrong direction.
Common channel grouping pitfalls
- Nonstandard mediums (
utm_medium=newsletter) falling into Unassigned or Other. - Link wrappers like
t.coandlnkd.intreated as referrals instead of social. - AI assistants hidden inside Referral, understating a fast-growing source.
- Comparing tools with different rule sets and expecting the same channel totals.
How VisitTrack groups channels
VisitTrack uses five channels: direct, search (Google, Bing, DuckDuckGo, Yahoo, Baidu, Yandex, Brave Search, Ecosia), social (X/Twitter including t.co, Facebook, LinkedIn including lnkd.in, Instagram, Reddit, TikTok, YouTube, Threads, Pinterest), AI (ChatGPT, Perplexity, Gemini, Claude, Copilot and others) and referral for everything else. UTM tags and ad click ids are stored next to the channel, so you can break any channel down by source and campaign — and, with revenue connected, by money. Check any referrer with the referrer channel checker.
Frequently asked questions
What are the default channel groups in GA4?
GA4's default channel group includes Direct, Organic Search, Paid Search, Organic Social, Paid Social, Email, Referral, Affiliates, Display, Organic Video, Paid Video, Organic Shopping, Paid Shopping, Cross-network, Audio, SMS, Mobile Push Notifications, Paid Other and Unassigned.
Why is traffic showing as Unassigned?
Usually because UTM values don't match any channel rule — for example a nonstandard utm_medium. Use standard medium values such as email, cpc, social and referral.
Related terms
- utm_mediumutm_medium is the UTM parameter that describes the type of marketing channel that sent a visit — such as email, cpc, social, referral or affiliate — and is what most tools use to assign the visit to a channel group.
- Direct trafficDirect traffic is any visit that arrives with no referrer and no campaign parameters, so the analytics tool can't tell where it came from and files it as "direct" or "(none)".
- Organic trafficOrganic traffic is visits that come from unpaid search engine results — Google, Bing, DuckDuckGo and others — as opposed to paid search ads, social, referral or direct traffic.
- Referral trafficReferral traffic is visits that arrive by clicking a link on another website that isn't a search engine, social network or ad — for example a blog post, directory, forum or partner site that links to you.
- ReferrerA referrer is the address of the web page that linked a visitor to the current page, sent by the browser in the HTTP Referer header and exposed to scripts as document.referrer.
Tools and guides
See which channels actually bring paying customers
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