Yik Yak started with colleges, but CEO Tyler Droll has his sights set on creating a product every bit as compelling as Facebook.

The anonymous messaging app, created by Furman University graduates Droll and Brooks Buffington in 2013, is now used by millions of students on more than 1,600 college campuses from Ireland to New Zealand. Users post text and photos, and people within a five-mile radius can then view them and respond.

See also: Anonymous messaging app Yik Yak now lets you share photos

The cloak of anonymity is a double-edged sword, though. encouraging users to be more honest but enabling others to go wild — a hard lesson the now-defunct app Secret learned before it shut down in April. In Yik Yak's case, anonymous posts, called "yaks," range from the sassy but harmless — "I know there's a drought but damn you don't gotta be that thirsty" — to the profane and offensive.

In response, some schools such as the College of Idaho recently banned the app from campus. Last fall, Yik Yak stirred up more controversy when a Los Angeles high school went into lockdown following ominous threats published on the app. (The company has since added a pop-up warning that appears if someone tries to post a yak containing a threatening word.)

Despite this downside, Yik Yak is proving a positive utility for times when students cry for help. Users feeling suicidal, for example, are met with encouraging comments from others. In less dire situations, students use the app to organize parties, dinners, study meetups and even dates. In fact, one 20-something couple who met on Yik Yak recently got engaged, the company said.

"We didn’t set out to build a dating app, a study group meet-up app or an app to let you know if your car was left on the parking lot," Droll, 24, tells Mashable. "We built this platform to connect you to your community."

The first-time CEO describes the process of managing a fast-growing startup as a satisfying process, but also "crazy stuff."

"I tell my friends, who come home from their jobs, [about my day] and for them, it's not like that at all," he adds.

Yik Yak has raised more than $73 million to date, including a $62 million Series B round last November, valuing the startup in the "low hundreds of millions of dollars," which it is pouring into expansion. The company's 45 employees just moved into a huge new office in Atlanta, where Droll and the crew are still in the process of getting settled.

A local muralist, for example, has spent over a week painting one wall, which includes a giant — you guessed it — yak.

"There are magic mushrooms dancing around," Droll says with a smile, showing photos of the work-in-progress design from his smartphone. "It’s awesome. His style is sort of weird. It’s funky. Hopefully, it'll be done by this weekend."

Decor aside, Droll remains heads-down on building out Yik Yak. Earlier this July, the company expanded the ways users can express themselves by letting them share photos on top of text — a feature the company slowly and carefully tested with a small group of users earlier this year.

Earlier this July, Yik Yak introduced the ability to share photos — a feature it carefully tested for several months with a small group of users. Image: Yik Yak

To thwart issues around nudity, bullying and sexual harassment, the startup has employees approving those photos before they appear in the app. That's a more hands-on process compared with much larger networks like Instagram, which allows users to instantly upload photos and tackles reported posts if employees think they violate company guidelines. However, Droll wants to err on the side of caution — for now.

"If we get to that point where humans can’t do it, there are a lot of user trust things we can put in place, like machine learning," he explains. "We can make it more scaleable than it sounds. But right now we’re doing well."

Yik Yak is exploring potential new features like introducing video and breaking up users' feeds in new and different ways. Broadening the service's appeal to folks out of college is top of mind, but Droll also points out the service will grow because of Yik Yak's existing users, who will graduate, move on and potentially keep posting anonymous Yaks — a trajectory not unlike Facebook's. The social network started as a college-only service but became the second-most trafficked site in the world, in part because its core audience grew up but remained loyal.

"Facebook nailed that," Droll says. "They didn’t build this one little thing. They built this platform where a lot can happen."

Maybe Yik Yak can do same.