The Internet is fueled by advertising – display banner ads, sponsored posts and articles, in-app ads, etc. According to eMarketer, the average person spends about 3 hours every day looking at their smartphone screen. With that level of engagement, companies know that ads delivered via mobile devices (including smartphones and tablets) are an important part of their media mix and their efforts to reach the right audience at the right moment.

Knowing the value and potential of mobile display ads, it's little wonder why the recent move by Apple to allow the addition of content-blocking extensions to Safari, has raised both fear and eyebrows. Instead of creating its own ad-blocking features, the company is allowing browser add-ons (available through its App Store) that can be set to block certain cookies, images, pop-ups and other content from being downloaded on the device. While ad-blocking browser plug-ins are already common on PCs, they remain rare on smartphones and tablets – until now.