"Why aren't you following me anymore???"
"What are you talking about? I'm totally following you. See? Oh. Hrm. I SWEAR I DIDN'T DO THAT, IT'S TWITTER'S FAULT."
"Oh yeah, sure." [MASS UNFOLLOWING ON ALL SOCIAL NETWORKS ENSUES]
The "Twitter unfollowed you, I didn't" excuse always seemed thin. Sure it did. Even if you'd witnessed some of the following/unfollowing weirdness firsthand. And I've seen a lot of it, since I unfollowed everybody a couple of months ago — the Great Twitter Nuking of 2011, the best thing I've ever done — right as the Twitter redesign launched. For weeks, Twitter would tell me I was following somebody that I wasn't.
But Twitter confirms now that it is a real thing, first over at TechCrunch, and (sorta) in their support documents. From what I hear, it's not quite what you think though. Twitter isn't unfollowing people for you — you're unfollowing them. Basically, you to go somebody's page that you think you're following, and it tells you that you're not following them, even though you are. So when you click the follow button, you actually unfollow them.
The unfollow bug, I hear, might be as old as the most recent Twitter redesign back in December, which makes a lot of sense, given the way Twitter rearchitected how it displays who's following whom — and at any rate, it's definitely been around for some time. Which is why it's not really a big deal, in a lot of ways.
Ironically though, the redesign that's behind the bug is exactly why the bug is so profound. Before the redesign, whether or not somebody followed you was not in-your-face information. You could see if somebody was following you, if you really wanted to (hold your mouse over the follow button on somebody's profile using Twitter for Mac, and it'll tell you if they're following you back). But you had to look. Or you might've found out when you tried to direct message someone, and couldn't. (Cue standard passive aggressive tweet: "I'd like to DM you but I can't!")
Now it's up front. John Herrman follows me. I am affirmed when I click on his profile. And if someone doesn't, there's an empty void. The redesign transformed followers and following from generic Twitter currency into something specific, direct, personal. It suddenly matters if you're following me or not. I can't not see it anymore.
So this is a bug of Twitter's own design, on multiple levels. Twitter coded it wrong, but it also set the stage for it to be an issue. It only adds to the richness of it that the bug is essentially a display problem. It's a bug about appearances, which matter more than ever on Twitter now.
P.S. First rule of Twitter happiness: Don't take it personally when people don't follow you! I don't! You shouldn't either.