When advertising online, you need to take into account one of the most basic factors of the audience you are reaching: what devices they are using. The most popular online advertising platform, in use by marketers of all sizes, is Google AdWords. Up until early 2013, AdWords allowed advertisers to set up separate campaigns to target mobile devices. Best practice generally entailed targeting mobile, desktop and sometimes tablet users in unique campaigns. Then, in a bold move to push the importance of mobile usability (some would say to drive up its own revenue), Google announced it would no longer allow campaigns to target by device, as part of what it called “enhanced” campaigns. Pay-per-click (PPC) managers made outcries about Google’s forced decision to remove control from advertisers, even cautioning people against upgrading immediately as the option became available to do so. A year later, the dust has settled somewhat as advertisers have adapted to the new campaign format. With the ability create device-specific campaigns gone, they’ve modified tactics with their campaign structure and bidding strategy to best reach people across multiple devices. Why should you care about who’s using a mobile device and who’s not? First of all, people often behave differently when browsing on a phone versus a desktop. In reviewing data from a site that received just over three million sessions over the past year, users spent an average of 2:42 when coming from desktop and 1:16 from mobile. That shows mobile sessions dropping off after about half as long as desktop sessions. A smartphone user might not care to spend time sifting through an extensive product inventory, instead just wanting a number to call or immediate directions to a location. Secondly, costs can vary widely by device. A study by Marin Software shows that the average cost per click on mobile was 26% lower than the desktop average in 2013. Also, the average cost per lead or sale might be more or less on mobile. Advertisers who take this information into account will see the need to control bids by device in order to maintain their target costs for leads. Thirdly, visits from mobile might provide more or less value to a particular advertiser. For example, the owner of an e-commerce website might find that desktop users put more items in their carts and spend more on average. Fourthly, you might want to drive mobile users to different pages than desktop users. Especially if your website is not responsive, you might have separate URLs for mobile. While a responsive website is ideal, your agency might be forced to work with a client’s existing website when running an ad campaign.