What does it take to make the 30 Under 30 list?  It's a question that we're asked often, and one that's a bit difficult to answer. Unlike the Inc. 500 list, which is determined by three-year revenue growth, America's 30 Under 30 Coolest Young Entrepreneurs is not driven by numbers. In fact, many of the companies on the list don't have any revenue at all; a couple of them don't even have a revenue model yet. Go figure. There's a hint in the name of the feature, of course: these young entrepreneurs are "cool." So what passes for cool these days?

Cool is when you leave a high paying job to start a company that helps impoverished women in the developing world gain economic independence (Gianna Driver of Gianna Fair Trade); cool is when you create a photo-sharing app that's on just about everyone's iPhone (Kevin Sytrom and Mike Krieger of Instagram); cool is when you build a Web-privacy platform that helps Egyptian dissidents evade government censorship (David Gorodyansky and Eugene Malobrodsky at AnchorFree); cool is when you cut a deal with Wordpress to power 18.6 million blogs on iPad before you've even officially launched your company (Jason Baptiste and Andres Barreto at Onswipe). And cool is when Oprah features your new product as a "must have" (Rochelle Behrens of The Shirt by Rochelle Behrens). What it all adds up to is a group of young people who are disrupting the status quo with new products and services that are making our lives better, simpler, more meaningful, and more fun. We think that's pretty cool.

This year, though, we had to sort through more cool companies than ever to create the list. In the spring, we put out the word through our social media channels that we were looking for 30 Under 30 candidates; we contacted alums from previous years and asked for nominations; we chatted up young entrepreneurs at Babson's Entrepreneurship and Innovation Conference, The Future of Entrepreneurship Education Summit, Kairos Summit, The Inc. 500 Conference, and many others; we tapped the staffs at Inc. magazine and Inc.com for great candidates; we checked in with Scott Gerber at Young Entrepreneur Council, and with the folks at Tech Stars and Y Combinator, the two most high profile tech startup funding and mentoring programs. And we asked the same questions over and over again: Who should be on the list and why? When we began hearing the same name more than once, we knew we had found a gem.

Throughout the process, it became pretty clear to us that there are more awesome people in their 20s starting companies than ever before. That makes our job harder, but it also makes our hearts beat faster. Because at a time when youth unemployment is around 19 percent, it makes more sense than ever for young people to take a leap of faith into the world of entrepreneurship. These days, it seems, the very best way to make sure you have a job is to create one of your own.

At the end of April, we put the final candidates on a spreadsheet, and we locked ourselves in a conference room at Inc.'s offices at 7 World Trade, where we debated the merits of each young entrepreneur. Eventually, a list began to take shape. Not just a list of hot tech companies, although you'll certainly find plenty of those on our list. We believe our list is a window into the next generation of entrepreneurs—a generation whose interests and talents are incredibly diverse. So in addition to some tech industry superstars, you'll find a burgeoning publishing empire, a food truck company, a private jet chartering operation, and a healthy fast food chain.

Part of what makes this feature so exciting for us is that it's a little glimpse into the future, as well as a reflection of the trends that have taken shape over the past years. For example, last year, we felt strongly that we had reached a tipping point with young female entrepreneurs, with nearly twice as many women-led companies on the list as in previous years.  This year, we're thrilled to report that the trend continues, with female founders or co-founders in one third of our 30 Under 30 companies. You'll also see that the list reflects a trend near and dear to our hearts, given our Manhattan home:  the startup scene here in New York has been exploding in the past couple of years, giving birth to young companies in the fashion, publishing, and financial industries. So this year, there are as many companies from New York (seven) as from the Bay Area.

Also worth noting: there are simply more entrepreneurs on the list than ever before. That's because last year we began honoring 30 companies, rather than 30 entrepreneurs. And because so many young companies are started with partners, that meant that our 30 Under 30 was really composed of 47 individuals. This year, the number rose to 52, with more than half of the companies having at least two partners. Is it any wonder? Sure, this is a highly team-oriented and collaborative generation, but there have also been some recent studies—including one from the Journal of World Business—indicating that companies started with partners have higher success rates. That's something our young honorees seem to understand intuitively.

Last of all, you'll notice that, for the first time, we have a not-for-profit organization on the list: Ankur Jain's Kairos Society.  In the past, the 30 Under 30 list has been comprised solely of for-profit businesses.  But lately, we've been discovering more and more young entrepreneurs starting and making an impact with their own not-for-profit organizations, and doing it in ways that little resemble traditional models in that sector. And so, going forward, we've decided to reserve one spot on the list for an exceptional not-for-profit organization started by a young entrepreneur.  Read Burt Helm's feature on Jain, and we think it will be crystal clear why we chose him.

So check out the list and vote for your favorite entrepreneur. And if you'd like to nominate someone for our 30 Under 30 Coolest Entrepreneurs list, drop us a line at 30under30@inc.com. We review nominations all year long!