San Francisco-based Discord is the brainchild of Stanislav Vishnevskiy and Jason Citron. Launched in 2015 as a platform where gamers can chat with one another, it has grown from just 20 users to more than 90 million worldwide. Its online platform is similar to social media in that it helps you connect with friends and strangers over shared interests, be it a videogame like Minecraft, or cryptocurrency and anime. You can create communities akin to Reddit's subreddits--chat rooms Discord calls servers--where you can connect with others through voice, text, or video. Joining and creating your own server is free, although in early 2017 the company introduced a paid subscription that offers some digital goodies like custom GIFs and a bigger file-size limit for $5 a month. Its popularity has attracted some superstar gamers like Ninja, a well-known Fortnite player who recently used the platform to chat with hip-hop artist Drake as they played together online. Discord currently has 100 employees, and it has raised more than $100 million from prestigious venture capital firms including Benchmark and Greylock Capital. It is not profitable yet. --Guadalupe Gonzalez

Technology is not only improving communication; it's also improving how we communicate. Exhibit A is DotCom Therapy. The three-year-old company was founded by two speech therapists, Emily Purdom and Rachel Robinson, after they realized they could provide services to children in remote areas more efficiently via telehealth. Purdom was spending two to three hours a day driving to rural schools to treat kids with speech therapy, while Robinson's wait list at an outpatient neurology hospital was nearing three months because of high demand. "You can imagine that if you have a child with disabilities or someone who suffered from a stroke, you want them to see a professional right away," says Robinson.
 
DotCom Therapy took in roughly $2 million in revenue in 2017, and it recently became profitable, after raising just $250,000 from friends and family. The founders now have 103 employees, serving patients in 28 U.S. states and seven countries. "We want therapy to be available to everyone, everywhere, and we take that pretty seriously," says Purdom. "When we look at our target market, it's not just the U.S.--it's global.” --Brit Morse

Emellie O'Brien sorts trash for a living on movie and television sets--but, no, she's not a garbage collector. She's the founder of Brooklyn-based startup Earth Angel, which helps productions become more sustainable by educating crews on best practices, using eco-friendly products on set, minimizing waste, and tracking carbon footprint usage. By adopting these practices, 29-year-old O'Brien says, productions can save $60,000 to $100,000 on waste bills and make a lasting impact. For instance, a scene from The Amazing Spider-Man 2 was shot in an area that was destroyed by Hurricane Sandy. Her efforts lead to the production crew planting new trees and fixing up the public benches for the scene. (The producers saved about $400,000 incorporating sustainable practices, according to O'Brien.) The four-employee startup, founded in 2015, "greens" about 10 productions annually. Earth Angel generated $250,000 in revenue last year, she says. While O'Brien admits the company is targeting a niche market, it has worked with some of the biggest names in the industry: Director Darren Aronofsky employed her for movies like Noah--even tweeting out her sustainability reports. Earth Angel also worked on the sets of blockbuster films like Black Panther, Ghostbusters, and The Avengers. --Michelle Cheng

More and more Americans are opting for cremation--so much so that it recently surpassed the number of annual burials. With her startup, Adelle Archer proposes a unique next step for honoring the deceased: turning their ashes into diamonds. Human remains contain carbon, which is the key element to creating the precious stones. Eterneva takes a portion of those ashes and, through partnerships with a diamond-growing lab in Amsterdam and cutters in Antwerp, turns them into a piece of jewelry. Customers can pick their design and color to best commemorate a loved one. The company stays in frequent contact with them throughout the eight-month process, providing monthly updates and, whenever possible, hand delivering the finished product. Archer sees the company as changing people's relationship with loss--and helping to eternalize their loved ones. "A diamond lasts more than a single generation," Archer says, "the way an urn of ashes won't." --Kevin J. Ryan

Cellular agriculture--the production of food and other goods from cells cultured in a lab or factory--has the potential to transform the world's food systems. That can't happen fast enough when it comes to the oceans, where virtually every major fishery is dangerously overexploited, according to the U.N. Food and Agriculture Organization. After studying biochemistry at the University of Massachusetts-Amherst and working as cancer researchers at hospitals in New York City, Mike Selden and Brian Wyrwas got the idea to bring emerging cell-ag techniques to bear on this problem. They relocated to the San Francisco Bay Area and enrolled in IndieBio, an accelerator for biotech startups. In September 2017, they finally got to taste the first fruits of their labors: carp croquettes whose main ingredient was cultured from stem cells. By the end of 2019, they hope to have a commercially available product consisting of fish cells bound together by food enzymes. Selden says it will be "a lot like the tuna mash for a spicy tuna roll. It's still fish. It's just fish cells that aren't in the shape people are used to having them in." The latter, something more akin to a fish fillet, requires more sophisticated tissue engineering and is likely two years off, he says. --Jeff Bercovici