So we all know that the official SD motto is “Fighting Ignorance since 1973 - it’s taking longer than we thought!”
So let’s come up with some unofficial ones!
How about
“We chew up monosyllabic words for breakfast!”
Any others?
All disputes should be settled by a round of Jello wrestling.
“Feh.”
Eutychus55 ate my balls!
ALL YOUR ATREYU ARE BELONG TO US!
Bork!
:wally
Hi Opal!
Wasting valuable time since 1973!
Don’t ask us about “-gry” if you value your life!
Finding ways for good discussions to end up in the pit since (whenever the messageboard got started)
“SDMB: We’re not afraid to shoot mimes.”
“Come for the 'Dope, stay for the beer!”
“Just Dope it.”
“Home of the Whopper… SPOOFE’s penis.”
“We sell spatulas… and that’s all!”
“Where men are men and women are satisfied, dammit!”
“SDMB: It’s the cheese.”
“Yo quiero Cecil Adams.”
“Cold or hot, SDMB hits the spot!”
“Our servers are slow because of the virus we’re uploading onto your computer.”
“SDMB… do you like… pie?!?”
“His name ain’t Czarcasm, it’s slythe, dammit!”
“The only place where you can say ‘Penis’ and not scare people away.”
“Oota-goota, Solo?”
“Straight Dope Inside.”
“Over one hundred billion stupid people shmacked upside the head.”
“It’s thinking.”
“Yes, you ARE surrounded by assholes!”
“Feel the wrath of Almighty Queen Lynn.”
“Ow, I stubbed my toe!”
“Cite, please?”
“Fighting drunken Scotsmen since 1973 (it’s taking longer than we thought).”
“Underpants.”
“Can’t we all just get a bong?”
“If you wanna be taken out of context, post here!”
“The ability to destroy a planet is insignificant next to the power of the SDMB.”
“McCloud?!?”
“Macho poseur assholes register here.”
“I’m not the messiah!”
“If you find a marble in the oatmeal, you get to drink from the fire hose!”
“How do I get out of this chickenshit outfit?”
“SDMB: Orcs and Humans.”
“Gotta catch 'em all!”
“I’m thinkin’ of something… orange. Something ora-a-ange…”
“Dope: Different.”
“We beat the pants off our competition… literally!”
“We’ll club this baby seal to make a better deal!”
“Do you feel lucky, punks?”
“I can ride a bike again!”
“Fighting Ignorance since 1974 (because of Daylight Savings).”
“Where you can moo with the best of 'em.”
“Now with new Lemon Scent!”
“It tastes more like fresh peanuts.”
“We’ll match anyone’s price or your mattress is FREE!!”
but does that require a silencer?
SDMB: Where bad jokes go to die.
Hijacks–they’re not just for airplanes anymore.
For the Fundies: Forget Ghod–fear David B.
If we can’t find the answer…it’s a pretty darn good question.
Remember how everyone has always told you that there are no stupid questions? Well, they were wrong.
The SDMB - more fun than a rabid wombat in your trousers.
“Teaching the world to do a decent cite since 1973 - It’s taking MUCH longer than we thought!”
The Straight Dope: Confusing Real Dopers for almost 30 years
The Straight Dope - Do You Agree With Cecil?
SDMB: The Jack Chick of Message Boards 
or–
Your Ass and A Hole In The Ground: A Comparative Analysis (completely stolen from a David Letterman Top Ten List)
Ah, it all makes sense now…
My contribution for SDMB slogan - “Work is for people who don’t have Internet access”
HEY! I named the poor bastard! A little courtesy here, toothpaste boy!
The Straight Dope - It’s Not Just For Breakfast Anymore!
SDMB - Hey, It’s All Been Done Before.
No Brains, No Wit - No Service!
The Straight Dope - For When You Have That Not-So-Fresh Feeling
SDMB - 4 Out Of 5 Dyslexics Think We’re Kinky!
SDMB: Got Anything Better To Do? Didn’t Think So.
More dopers visit the SDMB than any other message board.
Nothing outlasts a download from the SDMB. It keeps going, and going…