There are several web traffic referral sources. Organic traffic comes from search engines. Referral traffic comes from other websites. Display traffic comes from ads for your business on other sites. Paid traffic comes from promotions via sites like AdWords. Social traffic comes from social media sites. Each type of traffic can be further divided into individual traffic sources. For example, organic traffic can come from Google, Bing, or other search engines. And social traffic can come from a variety of sites.
Not all web traffic is welcomed. Some companies offer advertising schemes that, in return for increased web traffic (visitors), pay for screen space on the site. There is also "fake traffic", which is bot traffic generated by a third party. This type of traffic can damage a website's reputation, its visibility on Google, and overall domain authority.