What do data brokers really know about us?

What types of information are companies gathering about you? How can they use this information, or even trade it? And what rights to consumers have to learn how they're being tracked? Julia Angwin, senior reporter at ProPublica and the author of "Dragnet Nation" spoke with Hari Sreenivasan at the Aspen Ideas Festival in Aspen, Colorado to shine some light on these complex questions.