The ATF doesn't just want a huge database to reveal everything about you with a few keywords. It wants one that can find out who you know. And it won't even try to friend you on Facebook first.
According to a recent solicitation from the Bureau of Alcohol, Tobacco, Firearms and Explosives, the bureau is looking to buy a "massive online data repository system" for its Office of Strategic Intelligence and Information (OSII). The system is intended to operate for at least five years, and be able to process automated searches of individuals, and "find connection points between two or more individuals" by linking together "structured and unstructured data."
Primarily, the ATF states it wants the database to speed-up criminal investigations. Instead of requiring an analyst to manually search around for your personal information, the database should "obtain exact matches from partial source data searches" such as social security numbers (or even just a fragment of one), vehicle serial codes, age range, "phonetic name spelling," or a general area where your address is located. Input that data, and out comes your identity, while the computer automatically establishes connections you have with others.