SAN FRANCISCO - For Naval Ravikant, the problem with investing in start-ups boils down to coffee. “I got really tired of coffee meetings,” said Mr. Ravikant, 37, a technology entrepreneur turned investor.

“I thought, we’re dealing with Internet start-ups here, there has got to be a better, more efficient way to evaluate them than to do thousands of coffee meetings,” he said.

So in February 2009, Mr. Ravikant and Babak Nivi started AngelList, a networking Web site that allows eager start-up companies to pair up with investors looking to buy into the next Twitter or Facebook. More than 1,300 investors have already joined the site, including about 400 venture capitalists. The rest are angel investors, who buy a stake of a company with their own money.

On average, more than 20 startups from all over the world join the site every day, and about 200 companies have been financed. Mr. Ravikant and Mr. Nivi vet the investors before they are allowed on the site, which is free to join and has become hotter in Silicon Valley than many popular start-ups.

It is “one of the most innovative things that has happened in venture capital in the last five years,” said Dave McClure, an angel investor.

Mr. McClure is one of the most active investors on AngelList’s site, writing checks for up to $250,000 to dozens of start-up companies.

But some venture capitalists say AngelList adds more fuel to an already overheated market.

In 2010, venture investments grew for the first time since 2007. Investment in early-stage companies grew 15 percent from the year before, according to the National Venture Capital Association.

“We’re in a golden age of start-up innovation because the cost of starting a company has crashed through the floor,” said Mitch Kapor, the founder of Lotus Development, who recently invested $50,000 to $200,000 in companies he had found on Angel- List. “There is a huge flood of new companies; so many you can’t possibly find all of them on your own.”

As for Mr. Ravikant, he sees AngelList enabling start-ups from a wider geographic range to find the capital needed to build their companies. It is expensive for a start-up in Chile or Estonia, for example, to get coffee with an angel investor in Palo Alto, California.

Mr. Ravikant has been on both the investor and the start-up side, and his allegiances are unquestionably with the start-ups. After growing up with little money in Delhi, India, and then New York, Mr. Ravikant started learning computer programming languages as a teacher’s assistant at Dartmouth University in New Hampshire, where he delivered newspapers and washed dishes in the cafeteria to pay his way through college.

If some small start-ups fail along the way, and many undoubtedly will, that is no reason for concern, Mr. Ravikant said. “What is the harm if a bunch of rich, old people are writing checks to a bunch of young kids to go build start-ups and pursue their dreams and maybe create the next Twitter?” he said.

In recent months, AngelList witnessed its biggest investor frenzy yet, over a company called Green Goose, which describes itself as a “real-world game platform.” Green Goose makes tiny motion-sensing stickers that attach to everyday objects like running shoes or pill bottles. The sensors upload real-time data when an object is used.

Two angel investors committed $100,000 to Green Goose’s founder, Brian Krejcarek, after listening to him describe his product onstage at a start-up conference in San Francisco. “AngelList went nuts,” Mr. Krejcarek said. “I got a hundredsome e-mails from interested angel investors.”

Within days, he had hand-picked about a dozen investors and raised $500,000. “I’ve been eating ramen noodles for the last two years,” said Mr. Krejcarek . “I’d been pounding on doors over and over again without too many people listening, so the sheer volume of really qualified, interesting angel investors reaching out to me was overwhelming.”