Stanford CIS

The future of ad blocking

By Arvind Narayanan on

There’s an ongoing arms race between ad blockers and websites — more and more sites either try to sneak their ads through or force users to disable ad blockers. Most previous discussions have assumed that this is a cat-and-mouse game that will escalate indefinitely. But in a new paper, accompanied by proof-of-concept code, we challenge this claim. We believe that due to the architecture of web browsers, there’s an inherent asymmetry that favors users and ad blockers. We have devised and prototyped several ad blocking techniques that work radically differently from current ones. We don’t claim to have created an undefeatable ad blocker, but we identify an evolving combination of technical and legal factors that will determine the “end game” of the arms race.

Our project began last summer when Facebook announced that it had made ads look just like regular posts, and hence impossible to block. Indeed, Adblock Plus and other mainstream ad blockers have been ineffective on Facebook ever since. But Facebook’s human users have to be able to tell ads apart because of laws against misleading advertising. So we built a tool that detects Facebook ads the same way a human would, deliberately ignoring hidden HTML markup that can be obfuscated. (Adblock Plus, on the other hand, is designed to be able to examine only the markup of web pages and not the content.) Our Chrome extension has several thousand users and continues to be effective.

We’ve built on this early success. Laws against misleading advertising apply not just on Facebook, but everywhere on the web. Due to these laws and in response to public-relations pressure, the online ad industry has developed robust self-regulation that standardizes the disclosure of ads across the web. Once again, ad blockers can exploit this, and that’s what our perceptual ad blocker does. [1]

Read the full post at Freedom to Tinker.