I’ve written about selectively blocking content in browsers several times over the last two decades. In this post, I don’t aim to convince

Content-Blocking in Manifest v3

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2024-10-13 19:00:05

I’ve written about selectively blocking content in browsers several times over the last two decades. In this post, I don’t aim to convince you that ad-blocking is good or bad, instead focusing on one narrow topic.

Circa 2006, I was responsible for changing IE so that you could simply add an advertising site to the Restricted Sites zone and none of its script would load. Later, in 2010, I wrote a bit about the landscape of ad-blocking on the IEBlog.

More recently, Apple introduced Content-Blocking framework for their browser in 2015, and in 2019 the Edge team released Tracking Prevention, which blocks many ads in its Strict Mode.

Recently, there’s been a bit of an outcry about Google’s move to require Chrome extensions be built atop a new platform named Manifest v3. This long overdue change attempts to mitigate the overprivileged Chrome extensions framework. V2 poses security, privacy, and performance risks to users, and has been abused (intentionally and unintentionally) by extension authors over the years.

No good deed goes unpunished, however, and conspiracy theorists have argued that Google is doing this to prevent ad-blockers from working. These theories aren’t entirely crazy — Google is, after all, first-and-foremost an advertising company. Where the theory falls apart, however, is that Google’s ads are among the easiest to block. While MV3 may make it more challenging to block some ad providers, you can still trivially choke off more than half of Google’s ad revenue in under a dozen lines of code. If MV3 were a conspiracy on Google’s part, it’s a jaw-droppingly ineffective one.