By now, it's no secret that social networks (or really any websites) are sharing some of your usage data with advertising partners in order to provide more targeted ads. Most of the time, this data gets anonymized when it gets passed on so that there's no personally identifiable information attached to your browsing history. Or does it? I turns out that some social networks—including the majors that we all know and love—have an interesting definition of "anonymous," essentially making it possi