Googling for "world trade center kweer" turned up:
"Just Another Perfect Day" by John Varley.
The full text is online courtesy of Lightspeed Magazine, which printed the story in August 2011. The credit at the bottom says it originally appeared in Twilight Zone in 1989.
Other things have turned up missing as well. Things like Knoxville, Tennessee, Lake Huron, the Presidency of William McKinley, the Presbyterian Church, the rhinoceros (including the fossil record of its ancestors), Jack the Ripper (and all the literary works written about him), the letter Q, and Ecuador.
Presbyterians still remember their faith and have built new churches to replace the ones that were never built. Who needed the goddamn rhino, anyway? Another man served McKinley’s term (and was also assassinated). Seeing book after book where “kw” replaces “q” is only amusing—and very kweer. But the people of Knoxville—and a dozen other towns around the world—never existed. They are still trying to sort out the real estate around where Lake Huron used to be. And you can search the world’s atlases in vain for any sight of Ecuador.
....
And that thought is unworthy of you, since you know where this letter is coming from. She would not be offered to you as a bribe. The project managers know you well enough to avoid offering you a piece of ass to get your cooperation.
