Traffic is a count of the number of visitors to a website or web page, and the metric can be further defined by its source – for example, paid or organic search engine traffic, campaign traffic (from digital ads, emails, social media), direct traffic (direct visits perhaps following in-store promotions). A key aim for digital marketers is to increase traffic, and measuring it allows them to ascertain how successful different elements of their marketing campaign have been in bringing people to the website.