PHILADELPHIA - When venture capitalists proposed plowing $10 million into his information technology firm, Bill Loftus decided he needed help vetting their proposal.
"I needed to bring myself up to date on issues like what ownership shares venture capitalists were asking for now, what provisions they put in the contract to protect themselves, why they were asking for them," said Loftus, the owner of the Pennsylvania-based company Gestalt LLC.
He decided that the best advisers would be other venture capitalists. But many of those he had once dealt with had moved to new firms or other parts of the country. Rather than waste time tracking them down, Loftus looked to LinkedIn, a Web-based network he had recently joined.
Almost immediately, he was in touch with experts who gave him the advice he needed to knowledgeably negotiate the proposed investment.
Online social and business networks such as LinkedIn and Friendster combine the communications power of the Internet with the notion that friends of your friends, or associates of your associates, can lead to the next exciting job or the next great date.
Their sales pitch boils down to the idea that you are more likely to find a valued executive or the love of your life, by meeting someone through a trusted network of friends and colleagues than by browsing through Monster.com or Match.com.
Millions have responded to the philosophy by joining the online networks - 7.3 million at Friendster alone, according to analyst Nate Elliott with Jupiter Research.
The argument has also sounded good to venture capitalists and other investors who have poured about $30 million into the networking sites.
If you are thinking about joining a network, here are a look at the leading ones.
Anyone can join. Membership is free, but the network offers a $9.95 monthly plan that provides additional benefits, such as the ability to do advanced searches for other members by company and university affiliation, among other criteria.
Ryze offers scores of networks, although the four biggest networks, with memberships ranging to 6,500 people, revolve around business.
Ryze networks also organize live-world mixers and events.
Anyone can join. Membership is free, but is expected to eventually carry a fee of about $10 a month.
Primarily a business-oriented network, ZeroDegrees is distinguished by a clean, simple interface. Upon signing in, you can immediately invite friends to join the network, search your network for links to people who may be of help and to request an introduction to those on your network who are separated from you by several degrees.
You have to be invited by an existing member to join. LinkedIn is free, but the company has been contemplating charging fees.
LinkedIn is all about business and professional connections. In many respects, it is the most focused of the networks, providing a straightforward search utility for finding contacts and a utility for creating requests for introductions.
Anyone can join. Membership is free, but fees are under consideration for some services.
One of the first social networks, it also has grown into one of the largest. As the name implies, it is oriented to social networking: finding dates, friends or partners for specific activities, among other things. Members can search for contacts using a wide variety of criteria.
Anyone can join and membership is free.
Members can browse through job listings and services, as well as an area where they can ask for recommendations on assorted issues.
Tribe's greatest lures are the "subtribes" - ranging from a 17-member tribe interested in singer-songwriter Lucinda Williams to a 1,600-plus group hot to coalesce around 2004 political issues - and the live events organized by tribes.
An offshoot of Google, Orkut is a by-invitation-only network. Membership is free.
Orkut aims to connect friends, activity partners, business networkers and people looking for dates.
You can look for all those people by using a search utility, but also by browsing through its communities, including those organized around religion, computers, travel and alumni clubs, among many.
Its profiling questionnaire will take a long time and a lot of soul-searching to answer, typical questions being, "From my past relationships I learned ... " and, "In my bedroom you will find ..."
Online networking seems to have a strong appeal, even luring people once skeptical of the concept.
Peter Fader, a marketing professor at the Wharton School of the University of Pennsylvania, is a former doubter who now belongs to LinkedIn.
He said his network has grown to 90 people, including at least one professional contact with whom he was happy to reconnect after several years.
Fader said it has also benefited at least one of his students.
"She asked me to refer her to someone whom I found on LinkedIn, which I did," he said. "Later, she told me that it resulted in a conversation that was literally career-changing."