I just ran into the same problem that, apparently, countless bloggers have just run into: my blog stopped working. I couldn’t post, moderate comments, or do anything to change my blog. Every time I tried, I got an error, giving me this message:

We’re sorry, but we could not fulfill your request ….

Your Internet Protocol address is listed on a blacklist of addresses involved in malicious or illegal activity. See the listing below for more details on specific blacklists and removal procedures.

Your technical support key is: (deleted)

You can use this key to fix this problem yourself.

A link is then given to “fix the problem,” but it’s just a page which tells you that you’re a spammer or have been taken over by them:

Your computer’s IP address was determined to have recently sent spam or engaged in malicious activity as reported by a third-party monitoring service. This means your computer is most likely infected with viruses or other malicious software. See below for more information and removal instructions.

This I knew was BS–I use a Mac, and there’s nothing bad coming out of this system.

A quick search revealed the real cause: anti-spam software used by WordPress, specifically Bad Behavior, has screwed up in a major fashion and has blacklisted a lot of people who should not be blacklisted. Thanks a ton there.

So I went in and deactivated Bad Behavior, and the site works again.

But I also realized that this was probably also the reason why no one left a comment on the blog in the past 24 hours. If you tried to comment in the past day and got denied or told you were a spammer, my apologies; the problem is fixed now.

Bad Behavior, however, seems to be living up to their name; despite inconveniencing huge numbers of people, there was not so much as an apology on the site, just this explanation:

Update: Some people have asked for more details on what exactly happened. In brief, yesterday I moved all of my sites to a new dedicated server. In the process, I decommissioned an old blacklist I was running which I thought wasn’t being used, not realizing that Bad Behavior was still set to use it. Shortly afterward, I found myself locked out of my own blog, just as you all did. So therefore, this release.

Apology accepted. Man, what an ass–he takes on the tone of, “hey, I was inconvenienced too, so siooma.”

To make it worse, Bad Behavior did not give any clue in the process that it was responsible for blocking your site. Neither the initial error nor the less-than-useless “fix the problem” page gave any clear indication that it was Bad Behavior that was causing the problem. If I had not found references to the same error message in other people’s blogs via a Google search, I would never have guessed that Bad Behavior was the problem, and would have had to spend several frustrating hours trying to figure out what was wrong.

To the author of Bad Behavior: that is not just bad design, that is stupid design. What kind of software shuts down a site and then gives no clue as to what’s doing it? I may still use the software if spam increases while it’s off, but if I do reactivate it, I will take this idiotic design flaw into account and suspect Bad Behavior as the culprit whenever anything goes wrong.