This is aimed at the average computer user, who doesn't know what third-party cookies are, who doesn't know what retargeting means, who doesn't realize what giving facebook their email password does. It's a way to give that person tools to pick the degree to which they expose themselves, when the default is 100% exposure.
Basically, a family member asked me this question, and I thought it would be useful to write up for them. I figure folks on HN have the tools to figure out how they want to deal with FB and other services, but they may also want a resource to help friends and family who aren't so tech savvy.
If you are interested in the rationale for my objecting to 100% buy-in on facebook and have 40 minutes, I can highly recommend Maciej Ceglowski's talk at Beyond Tellerand 2014, the internet with a human face: http://vimeo.com/102717446