We A/B tested it, and the 750ms accordion produces maximum revenue. Why do you hate evidence-based decision making? /s

You jest, but that's exactly how you get plausibly deniable dark patterns. It's a numbers game.

Worse, sometimes the people who do it are completely unaware they are making a dark pattern, because they see the result of A/B test and convince themselves it's superior to what they think.

The ultimate version of this was done by Optimizely some years ago, where - let's assume here unintentional - bad UI design encouraged people to terminate their A/B tests early when the metrics favored the new version, leading to people without good understanding of statistics implementing dark patterns (or just stupid patterns), blissfully unaware that they've biased their own A/B tests so strongly that they could just as well be replaced by a piece of paper with words "NEW THING WORKS BETTER" written on it.

A/B testing is so gross. In other domains human experimentation of any kind, no matter how low risk, involves getting fully informed consent and ethics board approval before going ahead.

Experimental behavior manipulation, without even telling the subject they are part of a manipulation experiment? You would be chased out of the room and your reputation destroyed! Utterly unacceptable. But in webdev universe this is somehow seen as a totally normal practice.

This is exactly how users felt when Reddit ran A/B testing on their "feature" that forcibly signed out people on mobile browsers and said they needed to use the Reddit app to sign back in. I saw a crazy long thread of straight backlash about how messed up it was and how they aren't cattle to experiment on and how they didn't consent to that (which they prolly did in the T&C but no one reads that and actually understands what they're agreeing to).

Seeing as they were posting the backlash on Reddit, I'm guessing a lot of people downloaded the app to log in and Reddit said "Big Success!" when they checked the stats.

> which they prolly did in the T&C but no one reads that and actually understands what they're agreeing to

The GDPR's notion of informed consent really needs to be applied pervasively to all kinds of consumer contracts. If it's hidden in walls of text that the average user doesn't read it shouldn't count as consent.

I remember reading somewhere that if you actually read the TOS/EULA of every single thing you use, it would take your entire lifetime.

It maximizes their revenue until I decide to stop using Google. Joke's on them for not measuring long-term effects.