I don’t want to derail this discussion into something not directly Headset related (although in this case the question remains directly related), but why giving a helping hand in tracking all you do on your computer, they are already tracking your online habits and can build quite an accurate profile without even having a FB account (see Qwant Search Results )
Please understand I’m not arguing against anyone willingly opening such intrusive practices into his/her own life, I’m only arguing about your statement they can’t track you if your account is empty.