Domain

A domain is a site's human-readable name (like example.com) used in place of a numeric IP address, forming a website's base identity.

The domain is the web's base unit of organization: an analytics project is usually defined around one domain and marks the boundary of “my site.” A point that matters in analysis is the difference between a domain, a subdomain and a path: blog.example.com is a subdomain and example.com/blog is a path on the same domain, and the two behave differently for data collection and cookies. A common analytics trap is failing to stitch traffic correctly across a business's different domains or subdomains, so a user moving from the main site to the payment site is counted as two separate users. The domain plays into acquisition too: the linking site's domain is the “referring domain” from which the traffic source is built.