I operate a website visited primarily by both unsophisticated users and non-expert but savvy users (the former group being the demographic that exchange emoji-laden meme images on Facebook, and the latter group as the type of people comfortable getting around a phpBB board in the mid-2000s). I've seen a steady decline in AdSense/AdWords ad-revenue from visitors based on ad-impressions despite increasing visitor counts from those two main demographics - the evidence suggests they're using some form of ad-blocker.