Mysterious billboards are a thing now, I guess.

The latest one getting national attention is on Interstate 69 in Flint, Mich. White letters set against a blue background read: "I'm concerned about the blueberries." Well, sure, aren't we all? Michigan is a big blueberry producer, but local groups engaged in that business claim they're not behind the cryptic message, and CBS Outdoor, which owns the billboard, says it was posted anonymously and won't say more.

Theories abound. Some say it's about drugs (Oxycontin's street name is Blueberries, apparently). Others think it has to do with children or education funding, bees dying off or Obamacare. Personally, I'm hoping for a more exciting revelation. Maybe it's from Lena Dunham—she's wacky, right? Or Banksy—that dude's so in everyone's face! Maybe it's from the nation's strawberry growers—a prelude to an epic battle of antioxidants.

Those mystery NSA billboards in New York and San Francisco turned out to be from BitTorrent. That was … exciting. Right? Is anybody else getting a little bored with this trend?

UPDATE: Turns out Flint businessman Phil Shaltz put up the billboard, which is based on a personal and thought-provoking experience he had on a recent vacation. "This is a stunt. It was something I decided to put up to grab people's attention so they could start thinking about blueberries," he tells Mlive.com. "But now you need to make the transition to know what the heck I'm talking about. Blueberries are the concerns and the hurdles and the struggles that all of us deal with in a day."

The goal was essentially to make people see the world from the perspective of others. While vacationing in Alaska, Shaltz met a young tour guide who, when asked how things were going, said, "I'm concerned about the blueberries." Specifically, he was worried there wouldn't be enough rain for the state's blueberry crop.

At first, Shaltz felt like the 21-year-old was naive to be worried about such a specific issue, but he began to respect the young man's perspective and found himself wishing that others could be motivated to think about what's concerning the people around us. "We all go through the day and we see people who have blueberries—their own issues—and we don’t do anything. Even when it's not about rain, when it's something we can impact, we show just how desensitized we've become. We aren't as helpful to the common man in even the small things in life."

Shaltz admits his purpose with the mysterious billboard might prove unstatisfying to many who've been trying to guess its meaning. "There will be people who see this billboard and see this story, that are so disappointed that this is what it's about. Some people want it to be about racism or drugs or the school system, but it's all about something very simple and very human that touches all of us."