Referral

Referral traffic is a visit that reaches your site by clicking a link placed on another website. The term carries two related meanings: in web analytics it is one of the traffic-acquisition channels, and in marketing it is the mechanism of existing customers recommending a product to others.

How referral traffic works

When a user follows an external link, the browser typically sends a Referer header identifying the source address. Tools such as Google Analytics use it to attribute the visit to the referral channel and list the referring sites. Analytics separates several channels here:

• organic — unpaid search engine results,
• direct — visits with no identifiable source,
• referral — clicks from other sites,
• social and paid — social media and advertising.

Keep in mind that, due to privacy settings and the referrer-policy header, some sources are masked, and moving from an HTTPS domain to an HTTP one passes no referrer data at all.

Referral in practice

In SEO and analytics, referral traffic reveals which external links actually bring in visitors and convert them. In marketing, referral is the foundation of refer-a-friend programs: a customer receives a unique link or code and earns a reward when the referred person signs up or buys. The mechanism is cheap and effective because it rides on trust between friends — which is why it overlaps with the affiliate model, where commission is settled per completed sale.

How to measure referral performance

Settling a referral program relies on attributing each conversion to the right referrer. This is usually done with unique links carrying a user identifier, discount codes, or cookies stored in the invited person's browser. It pays to track not just the number of referrals but their quality: sign-up rate, the basket value of referred customers, and how many stay active after the first purchase. Referral traffic is also a valuable SEO signal — steady visits from a reputable site confirm that a link placed there is genuinely alive and drawing real people, not merely sitting in a search engine's index.