Traffic Sources: Where Your Users Come From
Traffic sources pinpoint where users come from using a Source/Medium pair, like google/organic. This tells you which channels—SEO, paid ads, or social—drive visitors. The footgun is confusing them: google is a Source, organic is the Medium.
Why it exists
To move beyond a simple visitor count and understand which marketing efforts are actually working. Without traffic source data, you're flying blind, unable to attribute success or failure to specific channels like SEO, paid ads, or email newsletters.
The mental model
Think of traffic attribution like a mailing address. The Source is the specific sender (e.g., "google.com"), and the Medium is the delivery method (e.g., "organic search"). Together, the Source/Medium pair gives you a clear picture of a visit's origin, like google / organic.
How it works
Web analytics tools categorize incoming traffic based on referral data. A visit from a search engine is tagged with a Source like "google" and a Medium of "organic" (for unpaid) or "cpc" (for paid). A click from another website gets a Medium of "referral." If a user types your URL directly, the Source is "(direct)" and the Medium is "(none)". You can also create Custom Campaigns to manually set these values for specific marketing efforts, like a "spring_newsletter" campaign.
When to use it
Use traffic source data to answer critical business questions. Which marketing channels provide the most valuable users? Is our investment in paid search (cpc) paying off? Which websites send us the most referral traffic? Are people finding us through organic search?
When not to use it
Don't treat every traffic dimension as equally important for every analysis. For a high-level channel performance report, Source/Medium is key. For drilling down into a specific ad's effectiveness, the Campaign and Content dimensions are more relevant. Also, be aware that the Keyword dimension is often "(not provided)" due to privacy protection on search engines, limiting its usefulness.
One canonical example
A user searches "buy widgets" on Google and clicks a paid ad. Their traffic data is: Source = google, Medium = cpc (cost per click), and Campaign = widgets_sale_q4. Another user clicks a link from a blog post. Their data is: Source = coolblog.com, Medium = referral. A third user types your URL from a bookmark. Their data is: Source = (direct), Medium = (none).
Interview question
A user finds your website by clicking a paid advertisement on Google. How would their traffic source typically be categorized?
- a.(direct) / cpc
- b.google / cpcCorrect
- c.google / organic
- d.google / referral
Why? this is the answer
The card explicitly states that for a user clicking a paid ad on Google, the Source is 'google' and the Medium is 'cpc' (cost per click). 'Organic' refers to unpaid search results, not paid ads.
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Read the original → support.google.com
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