SAN FRANCISCO, US: Chris Mirabile and Gianni Martire credit the founding of their social networking startup to a lame night out once upon a time in Manhattan.

The two twenty somethings met up with friends at one bar, only to find it was too crowded for comfort or audible conversation. They went to another, and found it too empty to supply much of a scene.

"It was a bust of a night," Mirabile said.

Instead of going home, the pair headed to a diner and spent the next several hours sketching out how they might develop a social networking application to improve their social lives. The result was The Hotlist www.thehotlist.com, developed late last year and beta launched in March, a tool for aggregating information about friends' social activities.

To date, the application has gained some traction, bringing in about 100,000 unique visitors in the past month, said Mirabile, the company's president. The co-founders also managed to secure early stage funding, raising an $800,000 round last week led by Centurion Holdings, the investment and advisory firm led by Joe Grano, former chairman of UBS Financial Services.

The New York-based company requires users to have Facebook profiles from which it can draw much of its data. It then combines data that users post about themselves on Twitter and Facebook with local reviews and listings in Yelp and other local content providers. Martire said that subscribers can use the site to find what groups of friends are doing and when, narrowing selections by geographic region or a particular social group, such as college mates or work pals.

The application is mostly designed for users in metropolitan areas, Martire said, where the sheer number of possible things to do can seem overwhelming. He said that the site has the largest concentration of users in California, followed by New York, Florida and Texas.

The startup is operating in a competitive space. Over the last two months, several companies with business models tied to organizing events and activities through social media have raised funding rounds.

Plyce, a Paris-based mobile social network that combines GPS and social data, announced in April that it raised about $400,000 in first round funding from Klima Ventures and Jaina Capital, two funds backed by prominent French web entrepreneurs.

Zerista, a site for organizing group events, announced in late April that it raised a non-disclosed seed funding round from Kickstart Seed Fund. The site offers tools for communicating with groups over mobile devices.

Foursquare Labs, a New York-based startup that runs as location-based service, has gained the broadest amount of attention lately. The company offers an application, accessible through mobile devices, which people can use to meet up with friends or earn rewards and recognition for patronizing particular venues. The company raised a $10 million funding round in late March, and is backed by Accel Partners, Union Square Ventures, Redpoint Ventures and Khosla Ventures.

It's unclear what kind of money is to be made in applications that marry location and social data. At The Hotlist, Mirabile said the plan is to make money through advertising and potentially in the future from venues that generate business through its service.

As for helping users improve their social lives, Mirabile said the application did at least work for its founders. Earlier this month, he and Martire decided to go out for drinks with some investors. They looked for a bar and found one on Park Avenue that seemed to have the right combination of attributes - a nicely balanced ratio of women to men, manageable crowd size, and some friends already there.

"We went, and everything was in line," Mirabile said.