so September 10
adj. Representing attitudes or ideas that were significant or applicable prior to but not after the terrorist attacks of September 11, 2001.
Also Seen As
Apparently, programmes like The Apprentice and Big Brother expose people to members of different ethnicities and that can only be a good thing.

And, actually, Phillips is right. Because if anything, watching Big Brother for any length of time has shown us that there are more rational reasons to really, really hate these people than simply the colour of their skin. After all, pigmentation prejudice is so September 10, darling.
—Ian O'Doherty, “Bob Geldof attacked by common sense,” Irish Independent, June 30, 2005
If you've heard something being dismissed as "so September 10" and been unsure what it means, this documentary about what goes on beneath New York's streets — from telephone wires to the subway — is a good example. Made prior to 9/11, it plays up large inconveniences such as burst water pipes or possible but remote threats such as earthquakes as imminent large life-threatening disasters, but then mentions the original bomb attack on the Twin Towers almost in passing.
—Kerrie Murphy, “Switch on,” The Australian, March 13, 2003
2001 (earliest)
Daphne Brogden is the former producer for nationally syndicated radio physician Dr. Dean Edell. Brogden, who now has her own Direct-TV movie show, called her old boss the other day to offer this story.

Brogden says she was at a rock concert with her sister after the New York and Washington attacks. The band's vain lead singer was preening and mugging on stage. After observing this behavior and hearing the singer repeatedly plug his new CD, Brogden told Edell her sister turned to her and said, "That's SO Sept. 10."
—Bill Mann, “The laughs come back, slowly,” CBS MarketWatch, October 04, 2001
Tired of the now "so Sept. 12" look of Semper Fi and "I Love New York" T-shirts, other au courant celebrities have taken a different, yet equally fatuous, turn in their attire of choice. Recently, such luminaries as Ben Affleck, Minnie Driver and Jennifer Blanc have been spotted in Christ apparel, T-shirts emblazoned with the following legends: "Jesus Is My Homeboy"; "I Love Jesus" and "Jesus Hates Your Botox."
—Lynn Crosbie, “Holy Jumpin' Jehosaphat!,” The Globe and Mail, January 11, 2003