Instead of picking up someone at a singles bar, today everyone just picks up their smartphone. One in 10 adults now spends, on average, an hour a day on a dating web site or app, according to Nielsen.

Apps are segmenting the market into increasingly absurd segments. Big fan of bacon? You can try Sizzl, a new dating app from Oscar Meyer. A fan of bearded dudes? Now there’s Bristlr. A fan of Apple products? You might find your next love on Cupidtino.

The explosion of dating apps is an outgrowth of changing demographics and the proliferation of smartphones. Pew research shows that 98% of U.S. millennials have a cell phone – increasingly often, a smartphone. And the number of unmarried adults has nearly doubled since the 1970s.

According to the Pew Research Center, in 2008 just 3% of all Americans said they had used an online dating site; today 9% of the adult population has. That kind of growth led to The Match Group’s surprising $5 billion valuation for its collection of sties and apps, including Match.com, OkCupid and Tinder. Its owner, media conglomerate IAC/InterActiveCorp, is going to spin off its dating businesses and offer an IPO soon.

Still, dating apps are a crowded field. Tinder is the current cultural pack leader, but there’s also Hinge, Coffee Meets Bagel, the popular gay app Grindr and up to 500 others on the Apple app store. Users don’t have to commit to any one app.

“In terms of revenue, the ­online dating industry has matured, but there are too many players, and not a lot are generating ­sufficient revenue for these sites,” said Britanny Carter, ­analyst for research firm IBISWorld. Total venture funding for digital dating companies is up overall, but only because there are so many players, according to financial data firm PrivCo.

One question is whether online dating can keep growing.

“Dating apps have a really disturbing paradox. The better you are at matching people, the more quickly your customers evaporate,”said Patrick Chung, co-founder and partner at venture-capital firm Xfund.

Of course, some have posited that we’re experiencing a sea change in sex and dating culture. Nancy Jo Sales explored this for Vanity Fair in September. She found a sex-obsessed generation of millennials interested only in “hooking up” who are feeding their desires with apps like Tinder.

Jon Birger, author of the book “DATE-ONOMICS: How Dating Became a Lopsided Numbers Game,” believes that the issue lies in the math: for straight, millennial, college graduates, the dating pool has four women for every three men. “When there are plenty of marriageable men, dating culture emphasizes courtship and romance, and men generally must earn more to attract a wife,”Birger wrote in the Washington Post. “But when gender ratios skew toward women, as they do today among college grads, the dating culture becomes more sexualized.”

Are dating apps undermining stable relationships? Hard to say. Pew research sees online daters getting married or entering long-term relationships a bit more often today than in 2008. But apps are a different demographic: The median online dating site user is 38 years old, while the median dating app user is nearly a decade younger.

Aziz Ansari, who wrote “Modern Romance” with sociologist Eric Klinenberg, suggests that apps aren’t that big of a departure. “Tinder actually isn’t so different from what our grandparents did,” Azari wrote in Time. “Nor is it all that different from what one friend of mine did, using online dating to find someone Jewish who lived nearby. In a world of infinite possibilities, we’ve cut down our options to people we’re attracted to in our neighborhood.”

Despite varying opinions, health scares, moral hand wringing, and the possibility of waning investment, bloom is still on the rose for dating apps. The industry is expected to grow by $100 million every year through 2019.