Some websites that serve ads have taken to blocking users who have ad blocking software installed in their browsers. Many other sites don’t block users, but do display messages asking users to turn of ad blocking for their site since they depend on the ad revenue to finance their operations.
Privacy campaigner Alexander Hanff claims that websites that do this are likely violating European Union regulations related to the storage of private data–the same law responsible for all those stupid “This site uses cookies” notices that now litter the web landscape.
Hanff posted on Twitter a copy of a couple pages of a letter he received from the European Commission after inquiring about this. The pages he posted suggest that under EU law, websites might first have to ask end user’s consent before they attempt to detect whether or not a user has ad blocking software installed.
This would seem to be an absurd result that would render a lot of normal, everyday interactions on the web suddenly illegal without affirmative consent. A lot of the replies to Hanff’s Twitter post note that this would seem to make illegal things as common as responsive design. It also seems likely that Hanff’s letter to the EU, which he apparently hasn’t published, may have mischaracterized how most sites implement anti-ad blocking.