One of the main jobs of Google Analytics is to get the traffic sources correct in your reports.
Organic search is the traffic that comes from search engines where source is the name of a search engine (that is in the default list of search engines of Google Analytics, or that has been manually added to your Google Analytics property's new search engine), and medium is “organic”. For example:
Referral is the traffic that comes from a non search engine website. i.e. The domain name of this website is not in the default search engine list of Google Analytics, or it has never been manually added to your Google Analytics property as a new search engine. Source is the domain name of the non search engine website, and medium is “referral”. For example:
Direct is the traffic that has no source. It happens when a user types in your site’s URL into the browser, uses a bookmark in the browser, or clicks a hyperlink (of your site’s URL) that automatically opens a browser. Source is “direct” and medium = “(none)”.
In web analytics, attribution refers to the method of crediting traffic sources to metrics or actions. The metrics can be a session, a page view, a goal conversion or other measurable events.
Let's consider an example.
Thank you for reading! If you love my book, you're welcome to donate through Paypal.