No problem, it's essentially the same as 4chan itself, although with less blatantly illegal content.
First part of the article (tl;dr summary follows):
On August 23, 2006, all hell broke loose in /b/. Things had been escalating for weeks; CP was posted by the bucketful, and rabid attacks on other websites were increasing. The source of what would be known as /b/-day started the day before, with a rush on myg0t, where many lulz and sadness occurred.
Then the levys broke. A small /b/tard splinter group went absolutely nuts on 3 different forums, completely ruinating them without a hope. Teen babies, feeders, and pro-ana nuts were completely obliterated from the Internets. Nothing was left untouched.
This was all combined with an increase of JB/CP related threads. The mods, being of special mental capacity, decided to do the unthinkable: enforce the rules for /b/. The posting of kiddie porn, jail bait, or raid information/requests (which had always been outlawed, just slackingly enforced) resulted in severe penalties. Moot posted the following notice:
The location of the secret Grey Area is actually Germany much to the disdain of /b/tards.
Policy Enforcement
Participating in a thread dealing with illegal content will get you globally banned for two weeks (thread starter is indefinitely banned). This means merely replying to it removes you from this site for a minimum of two weeks. This includes JB and any other "gray area" threads. Posting any piece of personal information or inciting/participating in an invasion of any sort will also get you, and anybody who replied to the thread globally banned. You have the option to either report or ignore (not reply to) threads that break the rules. Thanks!
Note: To clarify, this applies to THREADS breaking the rules, not REPLIES. If somebody breaks the rules in a REPLY the entire thread won't be banned. Again, exploiting this clause to break the rules will get you banned. These rules aren't anything new--we've just adopted a new way of enforcing them.
There is literally a "Ban thread" button now, so it isn't a chore to do. Abide by the rules and your own common sense.
/b/ now had rules. The entire board revolted; /b/tards turned on /b/tards. Everyone turned on moot. Absolute chaos ensued.
In the aftermath:
/b/ and most of 4chan was completely DDoS'ed.
There was a mass exodus of /b/tards, most likely to never come back
4chan will completely fucking utterly suck forever now, and lose most of its users.
Finally proved the statement "Only /b/ can destroy /b/".
Initially an obscure imageboard, 7chan became a new home to many exiled /b/tards and has risen to become one of the biggest chans on the internets.
And nothing of value was lost.
PROTIP: Banning DESERVING call-to-arms for raids was an absolute crock, as it is and has always been truly EPIC raids that united/still unite us moar than anything else, and give /b/ our historical aspect on teh intarwebs.
tl;dr:
moot made it so they could ban people who posted CP easily (and those who posted in the threads). Forum-goers QQed and went to 7chan.