I was a bit confused about how it's a prank on people at all. Ideally a prank is localized to one person and is set up so that it doesn't run out of control.
What happened to you?
Oh, I found the "Drop The Mic" button on my Gmail account, and thought it was a real feature. You can see the write-up in the linked article for more details.
I only heard about it after it was turned off, and spent my time since wondering if the news stories about the feature were the prank. (That is, that it didn't actually happen and Google merely announced they were turning off a feature that never existed... a kind of meta-prank as it were.)
I too was curious whether the complaints themselves were the joke, but I caught it early enough that I was able to verify the existence of the feature before it was pulled. It was definitely real. (And I tested its effect on outgoing email, it wasn't just a different-colored button.)
One of the most powerful rationalist techniques is noticing your surprise.
It ties in to several deep issues. One of them relates to one of my favorite LW comments (the second highest upvoted one in Main):
--pjeby
For the universe to make sense to you, you have to have a model; for that model to be useful, you have to notice what it says, and then you need to act on it. I've done many things the wrong way in my life, but the ones I remember as mistakes are the ones where some part of me *knew* it was a problem, and instead of having a discussion with that part of me, I just ignored it and marched on.
--Douglas_Knight
So any stories, of tricks you noticed, didn't notice, or successfully pulled?