When an outfit called Blue Security launched a service to go after spammers with vigilante justice, any idiot could've foreseen big problems.

In fact, an idiot did.

It wasn't a tough prediction to make. Vigilante justice is always a bad idea because it often results in innocent people getting hurt. And that's what happened, as a spammer's counterattack against Blue Security brought down thousands of blogs worldwide.Blue Security's business model is to identify spammers and launch denial-of-service attacks against them. E-mail users sign up for the Blue Security service. Every time a Blue Security-protected E-mail account gets a spam message, Blue Security sends an unsubscribe request to the sender's site. Not just one unsubscribe request--they pepper the sender with multiple requests for every single spam message received.

The plan is that eventually the spammers will have to stop sending their spam because every single spam message will result in stepping up the DoS attack on the originating site. (Blue Security denies it's a DoS attack, but of course it is.)

Blue Security's business model is certainly tempting. Spammers are sleazy, low-life thieves, stealing time and computing resources from honest, working people like you and me. Technology is only partly effective at stopping them, and laws like the U.S.'s CAN-SPAM Act are a joke.

Still, vigilante justice isn't the answer, because when victims resort to vigilante justice, innocent people get hurt.

And that's what happened. According to a report from TechWeb.com, a spammer launched a denial-of-service attack against Blue Security's Web site. Blue Security redirected the DNS address for that Web site to Blue Security's blog.

The problem: Blue Security's blog is hosted by a third-party service run by Six Apart, and Blue Security didn't even notify Six Apart, let alone get permission.

The redirected DoS attack against Blue Security brought down Six Apart's popular TypePad and LiveJournal blogging services. That brought down thousands and thousands of blogs around the world (including, by the way, my personal blog).

Blue Security denies it's to blame.

This isn't exactly what I predicted back in July. Back then, I predicted that Blue Security itself would start aiming its DoS attacks against innocent parties whom Blue Security thought, erroneously, were spammers.

What happened here is that innocent parties--Six Apart and its customers--got caught in the crossfire between Blue Security and a spammer. That's another common problem with vigilante justice: Innocent people get stuck in the middle.

Or, as one observer put it: "If my couch is on fire, I don't push it out of my house and into my neighbor's."

Spam is a problem, but Blue Security isn't helping solve the problem. It's only making it worse.

What do you think? Is Blue Security justified in trying to strike back at spammers?