We all start somewhere. But did you know that many incredible companies began as side projects? In fact, some of these ideas weren’t even meant to be companies. Now, they’re worth billions!

These powerhouses launched from humble beginnings. With persistence and skill, they scaled their side hustles into life-changing endeavors. From workplace tools like Slack to huge consumer brands in Under Armour, these are just some of today’s most prominent side hustle success stories.


By now, pretty much every employee and freelancer has used, or at least heard of, Slack. The chat app has revolutionized workplace communications in just a few short years. Today, it’s valued at $5 billion.

“Prior to Glitch’s closing, Slack was the team’s internal chat tool.”

Founders Stewart Butterfield (Co-founder of Flickr), Eric Costello, Cal Henderson, and Serguei Mourachov spent years laboring over another project, Glitch, a gaming platform that ultimately failed to connect with audiences. Right before the 2012 holiday season, Butterfield made the call to go from gaming to communications.

Why they went with a pivot to communications was simple: It was the only viable idea they had. What was once a team side project for internal communication became Slack. Prior to Glitch’s closing, Slack was the team’s internal chat tool. In the wake of Glitch’s failure to produce revenue, the team knew it could prove Slack’s value. In fact, it already had a concrete proof of concept, as Slack connected some key founders without them meeting for several years later!

When it launched in August 2013, 8,000 companies signed up for Slack on the first day, laying the path for its success today. Last month, Slack boasted 6 million daily active users. Pretty impressive for an internal team project, right? Slack’s story is a reminder to all entrepreneurs that an open mind and a willingness for discovery always creates opportunity. From there, it’s up to you to choose the right time to move.

Under Armour

Under Armour founder Kevin Plank’s journey began out of frustration in the mid-90s. At that point, Plank was a fullback and special teams captain for the University of Maryland Terrapins Football team. Like all players, he worked out a sweat each practice. Plank hated wearing a cotton t-shirt that would become a massive, sweaty burden as practice went on. Instead, he wanted something that would stay dry like his spandex compression sports.

By 1996, the 23-year-old Plank had graduated from Maryland and was now making his early Under Armour prototypes out of his grandmother’s basement. He gave the final products to college and NFL athletes he knew.

Feedback was positive, and soon Plank’s basement project became an on-the-road sales job. His hustling turned individual sales into team sales. Business took off. By the 2000s, Under Armour was asserting itself into the elite sports leagues. Today, it is a legitimate competitor to other major sports brands while being valued at $4 billion. Some of the best ideas begin in the most inconvenient places, don’t fret. Determination and a viable plan will take you to new heights soon enough.  


In 2006, Andrew Mason wanted to cancel a cell phone contract but only grew more frustrated. So in 2007, he launched The Point, a community goal-oriented platform to achieve missions. It was backed with a $1,000,000 investment from co-founder and chairman Eric Lefkofsky.  

The Point didn’t gain much traction as a do-gooder community until one group organized to save money. Mason soon took notice and considered making money saving ventures a separate page to house all the community activity. With the global economic collapse occurring, the board finally aligned and decided to make the switch to saving people money. It was then that Mason’s side hustle became a viable career option. In 2008, The Point became Groupon and focused solely on saving people money. By 2009, it raised its first significant funding, $30 million. In 2011, it went public with the largest IPO since Google.

In 2013, Mason was fired from Groupon after the company began to decline. However, the company has moved forward, including absorbing its once-biggest rival, LivingSocial. While Groupon’s brightest days were a few years ago, there’s no denying the incredible journey it’s been on. They sprouted at a time when they understood the market for a digital business, an essential step for all entrepreneurs.

Product Hunt

“The “Product” initially began as an email list managed by Hoover.”

Ryan Hoover had a sense he wasn’t skilled enough to build and engineer his own platform. But that didn’t stop him from creating a pretty impressive email list back in 2013. Hoover’s story of growth is purely strategic. With the goal to share new products between friends, Product Hunt meagerly began. The “Product” initially began as an email list managed by Hoover while he worked his Director of Product job at PlayHaven.

Flash forward a year and a half and Product Hunt announced its backing from seed accelerator Y Combinator. Just a few months later, and the once-mailing list became a series A-funded company, receiving over $7 million in investment.

In December 2016, Hoover’s venture was acquired by AngelList for around $20 million. Today, he runs his own angel venture, Weekend Fund.


An early innovator of the email list side hustle is Craig Newmark. You may better know him by his website, Craigslist. Newmark began his email list in 1995 after moving to San Francisco. Finding programming events in the area became hard to manage, he started work on his side hustle. Or, as he called it, an “Internet commune.”

Things took off and soon Bay Area locals added more than programming content to the list. The next year saw Craigslist become a web service. In 2000, it expanded out of the Bay Area and into other major cities when the company scaled its staff.

Today, Craigslist continues to operate as a mostly free marketplace for the Internet. Newmark and the website have often shot down chances for more substantial revenue and even took on former minority co-owner eBay in court over the years to preserve its vision. With Craigslist, Newmark shows the value in recognizing a simpler concept and building up!


In 2011, then-18-year-old Palmer Luckey began working on a project in his parent’s Long Beach garage. The idea stemmed from his years involved as a moderator of the virtual reality forum Meant to be Seen (MTBS). Palmer sought out to develop an affordable head-mounted gaming VR device – the origins of Oculus.

While working on the project, he attended college at Cal State Long Beach and worked part-time as an engineer for the University of Southern California’s Institute for Creative Technologies.

In 2012, Oculus launched a Kickstarter campaign, eventually raising $2.4 million. Palmer’s product wasn’t even out of prototyping when Facebook developed interest. Without a final product, the young inventor was able to sell his prototype for $2 billion. Looking at where VR is today, it’s safe to say all sides won on this deal.

Gmail, Google Maps, AdSense and More

From around 2004 until relatively recently, Google had a concept called 20% time. Essentially, Google empowered their employees to take one day a week to work on their side projects. In recent years, it’s declined into a concept that’s considered dead – and it still hurts.That’s because 20% time brought us some great ideas.

This initiative from Google set the standard for many tech companies who had entrepreneurial employees under their roof. It helped usher in ideas like Gmail, Google Talk, Adsense, and even Google Maps. By 2013, Adsense alone earned Google 25% of its revenue. Today, the concept is hushed with rumors that employees can’t take their eye off their demanding Google roles for a day any longer.

However, 20% time’s end isn’t the end of side hustles. Stories like Oculus, Under Armour and so many more highlight what hard work and education can bring you. If we’ve learned anything from our community of entrepreneurs at Skillshare, it’s that the best ideas sometimes just require some pursuit and they’ll come to fruition. Maybe it’s time to give your side hustle a bit more attention.