Remember the old adage not to pick a fight with someone who buys ink by the the barrel. Well, maybe there needs to a be a 21st century variation. Something like: don't tussle with a Web site whose online community numbers in the millions.

Say the wrong thing, and you might just get burned.

At least that's what I was left thinking after learning of the dust up between Fail Blog and Guinness World Records. It started last week when Fail Blog -- the Seattle humor Web site that showcases photos and videos of things gone wrong -- re-posted an entry from Guinness World Records' Web site that highlighted the record for the "Most Individuals Killed in a Terrorist Act."

If that weren't enough, the Guinness entry also included a link where readers could break the record.

A Fail Blog contributor circled that text and -- as is customary -- posted a giant "Fail" on the screen grab from the Guinness World Records' site.

Turns out the folks at Guinness -- which claims to be the "authority on record-breaking achievement" -- didn't like the attention and asked Fail Blog to take down the post titled "Record Breaking Fail" due to trademark infringement.

The editors at the Seattle Web site complied, but not before shooting off one of the more memorable letters we've seen.

It begins:

Dear Sir/Madam,

Thanks for writing us an email regarding the “Record Breaking Fail”. Unfortunately, douchebaggy cyber-bullying emails will only bring upon you more shame on your house. I am also resisting the urge to write this email in ALL CAPS.

I believe it is the duty of FAIL Blog(TM) to call out organizations when they encourage the public to do such things as “Break the record” for the “Most Individuals Killed In A Terrorist Act”. We firmly believe that our publication of your fail is protected under the concepts of fair use, commentary and non-trademark use. Please RTFM and we welcome you to teh interwebs.

Even funnier, Fail Blog ends the post by Rickrolling the lawyers at Guinness. The post has attracted more than 700 comments.