A new crop of genealogy Web sites are designed to recharge the oldest social network in human history: the family

In January, Bob Warden of Santa Rosa, Calif., received a rare e-mail from his 25-year-old nephew Christian. A link in the message directed him to Geni.com, a social-networking site where Christian had assembled a virtual family tree with names, pictures, birth dates, and e-mail addresses of the Warden clan, mapped out in pink and blue boxes. But Uncle Bob's help was needed: The tree was missing generations of aunts and uncles, cousins, and great-grandparents. Five months later, Uncle Bob's office is cluttered with cardboard boxes of old family photos and letters, and there are 538 relatives on the Warden family's Geni tree.

Geni takes up where the big social-networking sites have been known to leave off—family relations. "There are networks for friends, like MySpace. There are professional networks, like LinkedIn. But I thought a great omission was sites that help people stay in touch with their family," says David Sacks, a former PayPal executive who hatched Los Angeles-based Geni. Since Geni launched in January, a few hundred thousand users have started creating family trees, Sacks says.

But there's viral potential in the millions of "profile" pages these users have created. Each of these profiles is essentially a place card for every known member of a family, and users can e-mail invitations for relatives to join the project, filling in the profiles for their ancestors, themselves, and their next of kin.

Multigenerational Good Time

Geni isn't alone in its bid to take the age-old hobby of genealogy into the age of Web 2.0.

Ancestry.com, the leading Web site in the category, and others are adding a collaborative and social flavor to the simple desktop programs and Web sites individuals have been using to build family trees for more than a decade. These days, sites are offering MySpace-like community features so that relatives can work on their trees in tandem, share photos, access historical family documents, and create birthday calendars.

As with the Wardens, it's the younger, Web-savvier family members who frequently discover these sites and tip off their elders. But then it's often the baby boomers of the family who keep coming back: In April, 65% of the unique visitors to the top two family-networking sites were 45 or older, according to Nielsen//NetRatings (NTRT).

This older audience, an elusive market for regular online social networks, may be poised to swarm over family-oriented communities the way their kids do MySpace and Facebook. Unlike those sites, which have a relatively static, ad-supported model that users are accustomed to, family-focused online networks have taken a variety of approaches.

What Cost Family Roots?

Tree builders who want to dig deeper into history are paying for subscriptions to Ancestry.com, which boasts more than 2.5 million family trees. The site is the flagship service of the Generations Network, a Provo (Utah)-based company that in 1998 launched the Web site MyFamily.com and software named Family Tree Maker. Ancestry.com helps users dig through census records, newspaper clippings, military records, and other historical documents to build a vivid, interactive story of their families.

"We were a business focused on providing data and content to people. We're moving way beyond that," says Tim Sullivan, chief executive of the Generations Network. Over the past year, Ancestry.com has added a bevy of networking tools, including photo sharing and an audio-posting device that allows users to record family stories over the phone. It's free to build a tree and share it with others, but users pay an average annual subscription of $155 for access to the record books.

Visitors to Ancestry.com are gravitating toward the premium features—paid subscribers have increased 7.2% over the past 12 months, to 777,000. But according to Nielsen//NetRatings, the site has seen a drop in overall traffic. Unique visitors fell 17% to 3 million in April, vs. 3.6 million in the same month last year. This means Ancestry.com is getting fewer casual users and more avid family historians eager to pay for premium content.

By contrast, Geni is free and ad-supported. The startup has raised $11.5 million in venture capital, including a $1.5 million first round led by the Founders Fund, and a $10 million second round in February led by Charles River Ventures of Waltham, Mass. Since then, Sacks says, Geni has been striving to increase the site's "stickiness" with new features, including a "friends of the family" networking option.

Geni still has only minimal advertising, and doesn't plan on turning a profit until next year. Once there's a steady flow of families, more ads will start appearing and a fee may be charged for premium features. "It doesn't make sense to try to monetize users until you have a lot of them," says Sacks.

Privacy is an area being refined by many of these sites. Geni plans to let users choose how closely related someone has to be in order to view their personal information, or block individuals they mistrust. At present, though invisible to the public, user information such as addresses, phone numbers, and religious preferences can be viewed by every distant relative in the family tree. It's nice to learn you have cousins thrice-removed in Hungary, but maybe you don't want them showing up unannounced on your Ohio doorstep.

DNA Networking

One other type of family-networking site is on the rise: DNA testing repositories. Users of a service called the DNA Ancestry Project can swab the insides of their cheeks and send the samples to the lab to identify their 46 unique DNA chromosomes. Then, they can go online to see how their genetic material has mutated over time, research whether they're related to Marie Antoinette, or find out if they descend from the Babylonians.

"The exciting thing is you can match yourself to others on the database, and find out whether you are descendants from a common ancestor," says Dr. June Wong, vice-president of operations for Vancouver-based Genetrack Biolabs, the company that launched the site last November. In one case last year, a man who had been orphaned at a young age found someone on the site with a perfect DNA profile match—a cousin living on the opposite coast who helped him find his biological father.

DNA Ancestry Project participants pay $119 to $318 for a testing kit and membership, replete with online tools such as family tree building and surname searches. Users can keep their genetic info confidential or limit access to family members. But to search for matches in the worldwide database of users, they have to make their own DNA public. So far, Wong says, the site has signed up more than 2 million participants, with as many users in their 20s as there are older ones.

Others, including Google (GOOG), also seem to see powerful potential in linking people with generations of great-great-great-great-grandparents. Google recently invested $3.9 million in 23andMe. The startup (created by Google founder Sergey Brin's new bride, Anne Wojcicki) plans to charge $1,000 for an extensive genetic profile and features to help track down lost relatives. And on June 18, the Generations Network announced that it's partnering with a lab, Sorenson Genomics, to start building its own database of cheek-swab-generated DNA reports on Ancestry.com.

But DNA testing isn't a fit for all family tree builders. Geni user Bob Warden says, "It sounds spooky."