The original classified ad upon which the film is based first appeared in Backwoods Home Magazine in 1997. It was written as last-minute filler by John Silveira, an employee of the magazine, who is credited in the film as "Time Travel Consultant" and also has a cameo. The ad was later featured on The Tonight Show with Jay Leno (1992) in the "Headlines" segment, and eventually turned into an Internet meme before being developed into a screenplay.
There is an actual Facebook page for Liz McHollis, Jeff's old girlfriend who he looks up while in Ocean View. Anne Sellery and Jennifer Popochock, who were the hair stylists and makeup artists on the film, are her only two "friends." Her hometown is listed as Ocean Shores (which is a real town) and not Ocean View, which doesn't actually exist.
When the time travel ad is shown in the beginning, there are ads surrounding it for a Datsun and 1979 Hornet Wagon. Both of these cars are seen when the magazine trio is in Ocean View. Kenneth drives a first generation Datsun Z car and when Darius follows him to the "secure location" after he's done with work, they are spooked in the alley by a 1975-1977 Hornet Wagon, as AMC did not make a 1979 Hornet.
When Darius gives Kenneth her written phone number, it begins with area code 206, which is the code for Seattle and neighboring cities. The next three digits suggest Redmond, Washington, but, as per filming guidelines, his thumb obscures the last two digits.
When Jeff (Jake Johnson) approaches Kenneth (Mark Duplass) about the time-travel ad, he mentions that he would like to go back in time to see living dinosaurs. Kenneth later mentions being a fan of Star Wars to Darius (Aubrey Plaza). Director Colin Trevorrow's next movie would be Jurassic World (2015), which deals with an amusement park that features living dinosaurs and starred Johnson, and he has been announced as director of Star Wars: Episode IX (2019).