Most everybody has at least one. It may be buried in the back of a closet somewhere or wadded up in a pile, forgotten. Perhaps it's even clinging to your back right now, fitting you to, well, a tee.

The humble T-shirt has been a staple of daily life for what feels like forever, and the Internet has only enhanced humanity’s fondness for it.

All over the modern Web, a myriad of T-shirt websites pander to every nerd niche and pop-culture populace. Google virtually any interest you can possibly have—from Super Smash Bros. to antique WWII ships, Star Wars to Shih Tzus—and there’s a shirt waiting to be purchased. These communal clothing companies regularly mix and mash up properties, pulling together corners of pop culture that may never have crossed before in order to create a unique declaration of fandom. Often, all that effort happens for a shirt that’s only available on sale for a single day.

But how exactly can a shirt with Link cycling next to Batman and Harley Quinn exist in a world of DMCA takedowns, cease-and-desist letters, and stringent IP enforcement? Where do these designs come from and how can the sheer mass of these T-shirt sites all successfully operate? When it comes to the Internet-based economy of pop culture T-shirts, it turns out a few loose threads are holding the whole landscape together.

A trio of company lines

RIPT’s daily dose

Founded in 2009, Chicago's RIPT Apparel is one of many sites that offers daily T-shirt deals (right now, there are three) for a limited time on top of hosting other collections. Currently, RIPT's revenue is more than $4 million a year.

The RIPT process for designs arriving onsite is common within this industry: artists submit ideas directly. The company's three partners then pick from the roughly several hundred weekly submissions to land on which designs are going to be sold to the public.

"The daily model allows you to carry no inventory whatsoever," says Matt Ingleby, CEO and one of the founding partners of RIPT Apparel. “The designs that we sell, we print after they're sold... and really, for me, being in supply chain management, that was like kind of the Holy Grail of all companies. If you can run a company where you don't have to hold inventory, then you know, you're golden."

The submission review process means someone at RIPT has seen a design before it goes on the site. But again, like other shirt sites, the RIPT team was not made of legal experts. For that side of things, RIPT Apparel enlisted legal help right from the get-go to get a sense for what offerings could be considered legally in the clear.

"When we first started we actually worked with an IP lawyer (intellectual property lawyer), and every submission that we liked and we wanted to print we forwarded on to them for legal review," Ingleby says. "And after doing that for about six months or so... they would give us kind of a description as to why a design was legal or illegal to use. And after reviewing those for about six months, we felt like we had a pretty good feel for the legalities of designs."

Even so, RIPT does get a few Digital Millennium Copyright Act takedown requests a year. These continue to be something that they "handle right away," Ingleby says, by adhering to the guidelines RIPT’s IP lawyer helped establish. Generally, these aim for any RIPT design to be covered under parody and fair use guidelines.

As to why these products are as successful as they are—$4 million a year is no chump change—Ingleby says he thinks it comes down to how the designs are able to form a connection with consumers even if they aren't going to be understood by everybody.

"They feel like they're buying a shirt that doesn't have that mass appeal," Ingleby says. "And I also think... then they feel that if they see somebody, you know, as they're walking down the street, and that person understands their shirt or kind of gets the joke of the two different properties being mashed together and why that's funny, I think... it makes them feel like they're a part of something. And it says something about who they are, too. I think customers like knowing that maybe 75 percent of people who look at them have no idea what's on their shirt."