By the time the general election came, Facebook had introduced an interface that made the process much more robust. "They partnered with Acxiom and created an interface so you can simply upload any postal list that you want," campaign political director Josh Eboch told us by phone, "and they'll match it to your Facebook account and give you those users in an audience within a matter of hours." The match isn't only based on the email address you use to log in. "You can match postal addresses, email addresses, phone numbers, user IDs, if you have those, or even app IDs. If you have any of that data, they can use it," Eboch said. It's the postal address that's most useful "because it gives you so much more flexibility."
Think about that. Assuming you have a Facebook account, which you do, Facebook knows your email address. It probably knows your name, your birthday, where you work, where you worked, and who you're friends with. It knows far more than that, of course, both directly and indirectly. The firm that Eboch mentioned, Acxiom, also provides a wide swath of other data to Facebook, beyond what you've entered on the site or "liked."
This allows campaigns (as it does other advertisers) to target very, very specific groups of people linked tightly to the campaign's voter file. One of the best practices for campaign communication is to sandwich messages, layering a communication (like a piece of mail or a TV spot) with some other spur (like an email or a Facebook ad) both before and after. Cornyn's team could advertise to specific voters on Facebook before and after fundraising solicitations appeared in their actual mailboxes