Alexis Ohanian, 27, isn’t a billionaire (yet), but the Brooklyn resident is doing quite nicely for himself. He’s one of the co-founders of reddit.com, a social-news Web site that was acquired by Condé Nast in 2006 for north of $10 million; the terms of the deal remain confidential.

Give him time, though. With a new start-up –Hipmunk.com, a site aiming to make flight searches more user-friendly — and the return of easy money for dot-coms, Ohanian says it’s the go-go days all over again.

Getting noticed — and raising capital — is far easier than it was just five years ago. “Hipmunk launched in mid-2010 and CNN started gushing about it almost right away,” says Ohanian. “Compared to reddit, where after it launched, it was months before anyone paid attention. Today, it’s gotten a lot easier to bubble up and get popular.”

To some, this “irrational exuberance” sounds uncomfortably similar to what happened in the dot.com bubble of the late ’90s — when anyone with an idea, a mascot and a cleverly named site could launch a company.

Ohanian would have been only about 12 years old then, but he does question the valuation placed on a recent start-up, the phone-based application Color, which The Wall Street Journal reported as receiving $41 million in funding.

“I just don’t get it, it’s overvalued,” says Ohanian of the picture-sharing app, while attempting to locate it on his Android — with little luck.

“I’m surprised that Color would require that much money [in funding], but I’m more surprised that investors could get so excited about something that hadn’t even launched yet.”

After all, the barrier to entry is very low. Ohanian reasons, “it’s far cheaper to get a site online than it was, say, 10 years ago, when you had to have tens of thousands of dollars for stuff like servers. Today, cloud services do the hosting instead. Technology is less expensive now.”

So, if Ohanian doesn’t see Color becoming the next Facebook, what social networking sites or apps does he think will gain traction?

Surprisingly, in a world where oversharing has become commonplace, he cites LikeaLittle.com, a sort of Missed Connections for the college set, where users flirt and chat incognito in the hope of meeting in real life.

“People still appreciate moments of anonymity,” he says. “And this is virally growing through all the college campuses. Once [a site like this] becomes popular and integral to a person’s life, that’s when it can make money.”

He’s also bullish “on sites that get people doing actual social stuff, that use the Web as a way to interact in real life.” For example, there’s grubwithus.com, a communal dining site that describes itself as a place to “build friendships over food at your favorite restaurants. Meet new people and never eat alone.”

“It’s great if you’re new to a city,” says Ohanian. “It’s a comfortable setting. The menus are prix fixe and you pre-pay so it’s not awkward when the bill comes.” Thus far, it’s been established in five cities: New York, Chicago, San Francisco, LA and DC.

Most networking sites are geared toward young folks — “older just isn’t as sexy; most are marketed to college students, where they can get a high hit rate,” says Ohanian.