"Tweets are the greatest form of art in the 21st century."

Portlander Zach Katz is quick to let that slip when asked why he's framing and selling other people's tweets. Katz, 23, opened his business—including a website that lets you browse tweets by category—in May. In just a few months, he says he's sold over 50,000 pictures of tweets from celebrities, politicians and rock stars.

The most popular comes from Kanye:

Katz's inspiration? Boredom with traditional and "respected" art.

"The Mona Lisa, the Sistine Chapel…that's, like, fine," he says. But staying interested when browsing a museum proved an impossible task. "I just went on Twitter, and sort of held my phone up to the wall," he says. "And I went, 'Aha!'"

"Aha," indeed. After graduating from Emerson College in Massachusetts, Katz quit his job on a food truck and moved to Portland—which he describes as a "great place to do art"—to pursue his dream.

You'd think that framed tweets would be an insane investment. But Katz says he sells about 1,000 a week for $49 a pop. His website organizes the selection by topic or celebrity. The "Rare/Deleted" section is a highlight. A gem from the official @CarlsJunior account reads: "Hallelujah, y'all! Today, Miley Cyrus is legal."

"The hardest part is convincing people that it's true art," Katz says. When asked about the price, he basically shrugs. "I mean, a piece by Andy Warhol goes for about $11 million, so this is a steal."

Katz also sells tweets on Northwest 23rd—lining up a selection of framed tweets on the sidewalk across from a Salt n' Straw—in case you have 50 bucks lying around and want to buy a framed tweet by Kanye about getting emotional over fonts.

Basic math tells us that his two wildly different sales estimates—either 50,000 in total or 1,000 a week since May—have yielded $2.5 million or $637,000. Hmm.