What is a channel?
Channel or a marketing channel is a group of traffic sources with the same medium. It tells where traffic is coming from. Understanding how people are coming to your website is important. It informs you which efforts are working and which are not. Analytics allows you to zero in on the performances of different marketing channels to evaluate everything from brand awareness to social media messaging.
Organic search indicates the number of people who navigated to the web pages through search engines.
Direct indicates the number of people landing on your pages directly through URLs.
Traffic coming to your page through social media.
Traffic from video advertisements like those on YouTube.
Traffic from paid advertisements like on Adsense.