But sites like Rapleaf will quickly jar you awake: Everything you say or do on a social network could be fair game to sell to marketers.
Rapleaf, based in San Francisco, is building a business on that premise. The privately held start-up, whose investors include Facebook-backer and PayPal co-founder Peter Thiel, runs two consumer Web sites: Rapleaf.com, a people search engine that lets you retrieve the name, age and social-network affiliations of anyone, as long as you have his or her e-mail address; and Upscoop.com, a similar site to discover, en masse, which social networks to which the people in your contact list belong. To use Upscoop, you must first give the site the username and password of your e-mail account at Gmail, Hotmail, Yahoo or AOL.
By collecting these e-mail addresses, Rapleaf has already amassed a database of 50 million profiles, which might include a person's age, birth date, physical address, alma mater, friends, favorite books and music, political affiliations, as well as how long that person has been online, which social networks he frequents, and what applications he's downloaded.
According to TrustFuse's Web site, "TrustFuse has pioneered a unique e-mail address based approach to Internet data measurement. (It) provides a framework to learn about new customers, better market to these customers and...to better predict buying behavior." It continues: "We perform deep searches on people to enrich data on your users. And then we put the pieces of the puzzle together to give you the full picture."
In other words, Rapleaf sweeps up all the publicly available but sometimes hard-to-get information it can find about you on the Web, via social networks, other sites and, soon to be added, blogs. At the other end of the business, TrustFuse packages information culled from sites in a profile and sells the profile to marketers. All three companies appear to operate within the scope of their stated privacy policies, which say they do "not sell, rent or lease e-mail addresses to third parties."
Rapleaf CEO Auren Hoffman said the company does not use e-mail addresses and profiles developed by Rapleaf and Upscoop to deliver services for TrustFuse. Rather, TrustFuse's clients, which he said include presidential candidates and Internet widget companies, will bring it a list of e-mail addresses of their clients so that TrustFuse can perform fresh Internet searches on those people. Hoffman said TrustFuse will typically help clients understand which social networks their clients use so that they can market to them there. For example, a presidential candidate might want to know if his or her supporters are on MySpace.com or Facebook so they can approach people in that environment, he said.
"They say to us, 'I already know about her, but can you tell me these one or two other facts about her,'" Hoffman said. In effect, TrustFuse is a matching service between the marketers' e-mail lists and the online behavior of the people on those lists.
Apart from the unusual TrustFuse business, Rapleaf is among athat take advantage of the troves of public data on the Net--much of which consumers happily post for public perusal on social-networking sites and personal blogs. The search engines trace a person's digital tracks across these social networks, blogs, photo collections, news and e-commerce sites, to create a composite profile. , which might link to the same material over pages of search results or after trying different combinations of keywords, these sites attempt to "normalize" personal data so that it's easily digested by the searcher on one page.