For years, most of us have bemoaned the advertising that pops up when we use our phones and tablets. Recently Apple has enabled ad-blocking apps through its new mobile operating system, but now there is backlash as web publishers are fretting that ads on their sites can’t be viewed because of the blockers, threatening these publishers’ livelihood. All of this prompts a new discussion of the ethics of ad blocking. The bottom line is that advertising underlies much of how the internet operates, making it possible for free or low cost content to be offered, yet still allowing people to make a living off what they create. While ad blocking is not new, the number of people installing ad blockers is increasing and could hurt small and independent content publishers in particular, who depend on ads for 50 to 75% of their site’s revenue.