San Francisco-based RootsWeb, one of the oldest and largest online communities for accessing family history, will join MyFamily's network of Web sites, which also includes Ancestry.com and FamilyHistory.com.
RootsWeb will maintain its Web site address. Financial terms of the deal were not disclosed.
Hobbies such as family research have become big business on the Web. MyFamily, also based in San Francisco, has attracted financing from such well-known companies as CMGI @Ventures, Eastman Kodak, America Online, Compaq Computer, Intel Capital and Group Arnault, among others.
"There is no question that consumers are using the Internet to connect to their families, and we plan to put in place an aggressive program that will enable us to have the most complete network for families online," Greg Ballard, MyFamily chief executive, said in a statement.
The company makes money through advertising revenues, subscription services and e-commerce partnerships. Through today's deal, MyFamily will extend its reach and get more advertising space to sell through RootsWeb. It also can cross-promote its other family sites, such as Ancestry.com, which contains more than 600 million genealogical records.
RootsWeb will also expand its family history searches with added tools and content.
RootsWeb supports volunteer and nonprofit organizations such as The USGenWeb Project and The Free Births, Marriages and Deaths Project.