The Acquisition reports are all about where your visitors have come from before arriving on your website (previously called Traffic Sources).
They are incredibly useful for understanding the various marketing tactics that are encouraging visits and activity.
Organic Search: These visitors have used a search engine such as Google, Bing or Yahoo, and entered a keyword or phrase to look for a website that matches their requirements. They have then clicked on a SERP (Search Engine Result Page) from your website to arrive on your site.
Paid Search: These visitors have clicked on a paid advertisement such as Google Adwords or Bing Ads that has then taken them to your website. Please note: These ad accounts must be correctly integrated with Google Analytics to show in this Default Channel Grouping, otherwise these visits may be attributed to Direct or (Other).
Direct: Direct visitors know your website’s address and have typed it directly into their browser to visit your website, so haven’t searched, or clicked on another link. Often these visitors are regular, returning, staff or related suppliers. Direct also covers bookmarked links, and direct links sent in one-to-one emails or clickable in files such as PDFs, which don’t have an online referral source.
Referral: Referral visitors click on a link from another website that links to your website, e.g. a listing on yellowpages.com.au that includes your website link, or another blog that links to one of your blog posts.
Social: Visitors from social media channels are grouped under Social. Due to the varied tools used for monitoring social media channels, some might also be grouped under Referral or Other. This is where Campaign tracking is useful for understanding exactly where visitors are coming from. Despite this, the Social channel report is vastly improved in accuracy from when it was first introduced.
Email: If you send email campaigns from email marketing systems that include links to your website, these visits will be grouped under Email. However, you must integrate your email marketing system with Google Analytics, or select Google Analytics link tracking (options vary depending on your email marketing system). This channel will not collate any visits from clicks in a direct email that you send from your own email client (such as Outlook) to another user, just bulk emails like MailChimp.
Display: Similar to Paid Search, Display collates any visits from display advertising, such as Google Display banner ads. Again, Google Adwords must be integrated to show these.
(Other): Any visits that Google Analytics cannot attribute to the other Group Channel Groupings will be collated under (Other). Clicking on this link to view more details will usually show you what they are, often Social or Email.