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Bitcointalk At War With Ad Blockers

Op-ed - Bitcointalk At War With Ad Blockers

Over the past day or so, an ongoing arms race between the popular Bitcoin forum Bitcointalk and EasyList, by far the most popular filter list for the ad blocking extension Adblock Plus, appears to have reached a climax. In the recent past, Bitcointalk ads have generally slipped through ad blocking filters because they were relatively unobtrusive, appearing as small blobs of text in between the first post and the rest of a forum thread. On May 20, however, a Bitcointalk member posted that Adblock Plus was now blocking the ads. Within three hours, Bitcointalk operator Theymos posted the following:

Not anymore. Wink

They tried this once before with the same simple blocking method. I have a bunch of obfuscation techniques in mind if they try anything more fancy. It’s much more difficult for them to block the forum’s ads because they’re 100 inline and not images.

Over the next few days, it appears that the EasyList maintainers managed to break through Theymos’ obfuscation multiple times, and each time Theymos found a new way to circumvent their strategies. On May 25, Theymos posted a longer update saying:

Let’s see ’em block this. There’s now a random number of invisible “posts” before and after the ad, and they’re all (I think) indistinguishable from real posts if you’re limited to just CSS selectors. Hopefully the filter maintainers aren’t careless or they’ll end up blocking random posts.

At this point, however, Theymos proved to be very wrong. Theymos made a post on May 26, entitled “Adblock Plus censoring posts”, saying:

The Adblock Plus EasyList maintainers couldn’t block the forum’s ads, so they just blocked the links in the ads everywhere on the forum. So that’s why you might see posts censored like this:

At Private Internet Access, we provide multi-gigabit tier-1 access points to our private global VPN (virtual private network).

Why VPN?
Please visit our website, , at .

We look forward to providing you the highest quality .

There’s nothing I can change in the forum’s HTML to stop this. This isn’t a side-effect of my anti-ABP code. If you don’t want posts censored, you need to disable ABP (or just these filters) on You can complain about it here.

The incident is interesting because it poignantly, and hilariously, shows at just how high a level of abstraction modern commercial cyber-warfare can take place. Here, the battlefield is forum readers’ eyes, the munitions are lines of Javascript code inserted into files are ultimately downloaded and run on users’ browsers, and the civilian casualties are readers and users of the forum. In a normal war, individual battles take place in one of the countries whose government is a combatant; here, users are continuing to voluntarily use Bitcointalk and Adblock Plus, and so all of the “civilian casualties” involved are essentially citizens of both “countries” at the same time – where citizenship is defined as having a habit of asking one’s browser to ask the “country’s” web server to send their browser data representing a web page (or an ad-blocking script) via the hypertext transfer protocol.

It is important to note that Adblock Plus does have a profit motive here; the company maintains a list of “acceptable ads” that they allow to pass through their filters (although there is a setting for users to block them), and although inclusion to the list is “free for websites and small businesses” they have been known to charge for it. However, this may be the “least bad” solution the site’s owners can come up with; it allows them to continue providing a service valuable to millions of people for free, all at the cost of a slight (and even optional!) loss of neutrality. Nevertheless, website owners have good reason to dislike it, and so events like these are only going to increase in the decades to come. The economics and game theory of the internet is proving to be a field that we have only begun to explore.