At 5pm today the unruly message board 4chan plans to take down the blogging platform Tumblr. 4chan has successfully cowed everyone from Gene Simmons to the Tea Party, but they may have finally met their match.

Tumblr users are freaking out about today's attack, the culmination of a campaign, "Operation Overlord," launched by 4chan to pay back Tumblr for encroaching on their turf. That turf being making dumb jokes and harassing strangers on the Internet. If you see 13-year-old girls running from their homes weeping at 5pm today, Operation Overlord is why.

We're all familiar with the anonymous hivemind that festers on 4chan's /b/ message board, occasionally lashing out at women who throw cats in trash cans. Maybe less known is Tumblr, a minimalist blogging platform that encourages sociability by letting you follow people, Twitter-style, and easily reblog their content. Launched in 2007 by Brooklyn hipster-geek David Karp, Tumblr is the cutesy counterpart to 4chan's gore-and-porn carnival. The Tumblr clique has its own in-jokes—animals dressed as hipsters, mainly—and its own powerful mob dynamic.

There's a lot of overlap between 4chan and Tumblr, as each is comprised largely of teenagers who spend far too much time on the computer. (And old media organizations trying to seem hip.) 4channers constantly gripe that Tumblr users poach their jokes and memes, which, while true, is not much of a complaint when you consider the material they're talking about: Cat memes, lolspeak, Pretty Cool Guy, etc. Tumblr also joined in on the 4chan-led harassment of viral video star Jessi Slaughter.

Tumblr users took it too far recently by pranking a popular 4chan target, the chat site Omegle. (Think text-based chatroulette.) So 4chan launched Operation Overlord with the intention of creating fake Tumblr profiles to fill the network with porn and gore, and ultimately take down Tumblr with a DDoS attack—a flood of traffic that will crash their servers.

But Operation Overlord backfired. Tumblr users quickly learned of the plan and passed around warnings and "survival guides" via Twitter and Tumblr. A Tumblr counter-attack is planned for tomorrow, where Tumblr users will flood 4chan with their own version of porn and gore—less visceral, but just as repulsive. One Tumblr-er urges:

1) harry potter

2) mean girls

3) anti twilight

4) space, triangles and helvetica

5) WHAT IS AIR

6) just mention tumblr like, every single post

7) nutella

8) hipster kitty

For once, 4chan users are doubting their role as the Internet's dominant hive mind. Some samples from today's 4chan discussion of Operation Overlord:

Holy shit i can't believe the amount of fail

Game Over, we failed. Too drawn out, too public... Tumbfag already knows we're coming and has already fortified against us.

Well this is just embarrassing for everyone.

But maybe a truce is in the offing. Wrote one 4channer:

EVERYBODY STOP tumblr is all girls 4chan is all guys we should fuck!

The Internet is a mall.

Update: Well, it's nearly two hours past D-day, and it seems that 4chan is down but Tumblr's still going strong. Um?

[via Urlesque and Downforeveryoneorjustme.com; image of Operation Overlord flyer via Enyclopedia Dramatica]