This is the Denny ‘s headquarters here in Spartanburg, SC. I have a theory that Denny ‘s Tumblr page is ran by some ex IT guy in one of the offices here. He got booted from IT because he tried to hack into IHOP and Waffle House.
His demotion has caused him to go insane and now he sits in an office, all alone, making nonsensical posts on tumblr. If you stare up at the building at anytime between 9 pm and 12 midnight on the 3rd Wednesday on an odd numbered month you may see the office window open and a dim flicker of what appears to be a computer screen scrolling down a Tumblr dashboard.