Louise Matakis put together a guide on how to manage your online personal data, and figuring out who buys, sells, and barters it.

Personal data is often compared to oil—it powers today’s most profitable corporations, just like fossil fuels energized those of the past. But the consumers it’s extracted from often know little about how much of their information is collected, who gets to look at it, and what it’s worth. Every day, hundreds of companies you may not even know exist gather facts about you, some more intimate than others. That information may then flow to academic researchers, hackers, law enforcement, and foreign nations—as well as plenty of companies trying to sell you stuff.

A good guide as usual from Wired.