Defense in Depth (Score 1)

Give some thought to blocking at different levels. Blockers in browsers are obviously very limited to that browser's traffic. The hosts file can be effective for all traffic from a single machine. DNS blocking can be quite effective. For example, OpenDNS allows 25 domains to be blocked with their free plan, more with their nominal cost paid plan. Their Umbrella product works well for mobile and cellular devices that don't go through your own router. These are all very easy solutions, and either free or low-cost, with little setup required. Defense in depth allows blocking at the appropriate level for a given threat. Regarding the ethics of blocking ad content, I suspect most people wouldn't object to unobtrusive ads per se, but unfortunately most major sites incorporate numerous tracking services, so ads come with a serious sacrifice to online privacy.