Marco Arment: The Hero of Apple’s Appageddon

July 6, 2012, 11:57 AM UTC

Arment’s Twitter headshot

FORTUNE — Late Thursday, Apple (AAPL) public relations reached out to several news organizations — including the Wall Street Journal‘s All Things Digital — to alert them that what it described as a “temporary issue” that affected “a small number of users” had been “rectified.”

Apple PR apparently neglected to reach out to Marco Arment, a co-founder of Tumblr, the creator of the popular Instapaper app and a iOS developer with an unusually large following through his blog, his Twitter account (@marcoarment) and his Build and Analyze podcast.

That may have been a mistake.

It was Arment who first spotted the problem two days earlier when Instapaper users began complaining that his latest update crashed immediately every time they launched it. Arment e-mailed Apple’s App Review team and started “yelling” about it on Twitter. Within two hours a working version of Instapaper appeared on the App Store.

But he soon realized that the problem was more widespread than just his app. Over the next two days he compiled a list of more than 100 apps whose updates worked perfectly when they were submitted to Apple but were corrupted when they arrived at the App Store. He warned users and developers not to update their apps until the problem was corrected, and he issued an urgent request — in boldface — to Cupertino:

Apple: This is a serious problem. It’s not isolated. Please fix this.

So when Arment saw Apple’s press statement on someone else’s blog, he couldn’t resist posting a correction:

“It’s probably worth nitpicking ‘a small number of users’: Based on my cumulative stats for July 3, Instapaper’s corruption alone probably affected well over 20,000 customers, and there were over 120 other apps affected, including some very big names such as Angry Birds, GoodReader, Yahoo, and the LA Times.”

Apple’s “temporary issue” was, in fact, the App Store’s worst bug in four years of operation — a meltdown that Wired dubbed “Appageddon.” It was ultimately traced, as Arment correctly anticipated, to an issue with a server that applies Apple’s digital rights management protection to apps before they are released.

Arment was pretty easy on Apple, all things considered. He pointed readers to a MacWorld report that the company might be removing the one-star ratings many apps had unfairly received during the meltdown. “I wouldn’t have predicted that,” Arment wrote. “If they do, it will go a long way toward repairing their relationship with the affected developers.”

He was not so kind to the more than four dozen tech reporters who piled onto the story, often without giving him credit or — even worse — trying to make it sound like it was their scoop. In a series of tweets he calls “Rewrite Bingo,” he covers the press coverage. You can read it here.