As I reported earlier while the news was breaking, at 9:27am eastern, all Google search results appended This site may harm your computer to the top of the listing. The topic was wildly speculated on Twitter as everyone tried to decipher the problem.
At first it was reported that perhaps outsourced malware partner, the non-profit www.stopbadware.org was responsible. Stopbadware.org quickly rectified the confusion with a blog post declaring that it was in fact Google that caused their site to crash as millions of people followed the “This site may harm your computer” links back to their site.
It turns out it was human error at Google, when a likely now fired technician, entered the ‘/’ character into the database as a component of all URLs that contain malware. Of course there is a ‘/’ in EVERY URL ON THE WEB!!! Marissa Mayer* describes the problem thusly on The Official Google Blog:
Unfortunately (and here’s the human error), the URL of ‘/’ was mistakenly checked in as a value to the file and ‘/’ expands to all URLs. Fortunately, our on-call site reliability team found the problem quickly and reverted the file.
By quickly they meant the problem only lasted one hour. For one hour EVERY PAGE ON THE INTERNET was reported as Malware.
The ‘/’ is truly mightier than the sword.
What does this mean for Google search? I don’t know, but for me it brings Google’s search dominance and lack of any real competition into acute focus.
*Thanks to Matt Cutts for the correction.

Jesse – great scoop!
Just a quick comment that the blog post was by Marissa Mayer.
Very nice write up, Jesse. Thanks for all your informative tweets. Your Twitter feed is one of the most content-rich that I follow.
And you’re a good singer, too.
I wonder what character was meant to be entered instead of ‘/’
I would hate to be in the position of the probably new tech who made this mistake. I hope he/she will be able to move on after this one.
Hehe. I hope now Google is considering implementing a feature that lets admins “preview” the number of sites that will be affected by a change they make to the malware db. In fact, I’m surprised they don’t have something like that already. Or maybe they do and said admin was being lazy.
[...] How One Misplaced Character Caused A Google Meltdown | Jesse Newhart Good reason to double check your work [...]
ha