Facebook and Google are the 800-pound gorillas in online advertising because of audience reach and superior targeting. They enjoy another lesser-known advantage: they're largely immune to ad blocking. People install ad blockers to strip out marketing messages and the trackers used to target ads. They're more widespread on computers but they're migrating slowly to mobile too. Adoption varies by country, as the chart below shows. Analysts estimate that ad blocking cost web publishers nearly $22 billion in lost ad sales last year, compared with total internet ad sales of $160 billion. Yet it's becoming clear that the pain isn't being shared equally, and this is more bad news for newspaper, magazine, and television companies. What started as a consumer movement sparked by rage about intrusive ads, security and privacy seems to be strengthening the internet's big beasts. Get the full story at Bloomberg