The database seems to bring together information about supporters gathered from all branches of the campaign -- everything from an individual's donation records to volunteer activity to online interactions with the campaign -- aimed at allowing the campaign to personalize every interaction with potential supporters.
Earlier this month, we built an interactive graphic showing how different Obama supporters received different variations of the same email -- one way that the campaign may be using data to personalize messages.
The reason we can't speak with certainty about the campaign's database is because Obama's campaign won't talk about it. Citing concerns about letting Republicans learn their tactics, the Obama campaign declined our request for comment -- just as they have with other outlets -- about what data the campaign collects and what they're doing with it. The campaign did emphasize to us that, regardless of what information they gather, it has never sold voter data or shared its voter database with other candidates.
For a guide to what we know -- and what we don't -- about the information Obama is collecting about voters, read the full story here.