For those that don't know a credit header is information in a credit report that gives identifying information about a person. Credit headers contain:
Name, AKA's, Maiden Name, Date of Birth, Social Security Number and Issuing State, Relatives, along with Current and Previous Addresses which can go back 25+ years.
Credit headers have been ruled as to NOT be part of a credit report:
<blockquote>A credit header is identifying information from a credit report. It includes name, mother's maiden name, date of birth, sex, address, prior addresses, telephone number, and the Social Security Number.
Credit headers came into use after the FTC changed its definition of a credit report in the course of settling a case against TRW (now Experian). The FTC allowed the CRAs to treat headers as "above the line" information and to sell it with no legal protections for the individual. The reasoning was that this information did not relate to credit, and thus should not be considered part of the credit report.
Credit headers are used for location of individuals and for target marketing. They are sold in bulk by the CRAs and can be purchased online.</blockquote>
Google can simply take your IP address, trace it back and then run your name against the header database to locate individuals in your area with that name. The more unique your name the easier you are to identify. If you have a common name it would be further cross-referenced with other information like relative names or maiden names. Once identified they have your complete life history.
What do you think they could achieve (monetarily) having a personal history attached to a social account? I can tell you the first thing I'd do is determine your influence. I could take your addresses/family addresses and reasonably determine what kind of spending power you have based upon cross referencing your address with tax information. On top of that I don't have to necessarily know about you in another country. I can simply define the influence of an individual here and you may end up in their circle of influence. Imagine a person that's been voted as highly influential in said system and they communicate with you on a regular basis. From that I could infer that you are also potentially influential.
Other countries have similar systems. The information may not be as freely available but it's there. It just needs to be harvested.
For example, one of the biggest sources of relative information is obituaries. Something that is freely printed all over the place.
The more information they have access to, well ...