Facebook offers the treasure of valuable information on data of users to its advertisers, who can target the Facebook's users to find their audiences. From this bowl full of information of its members Facebook made $40 billion after the Google's revenue.
There are 50000 unique ways the advertisers target the Facebook's users including Demographics, interests and behaviors. Different advertisers target their audiences in different ways, lets take a look.....
Demographics - You define your age, gender, location, relationship status, occupation, employer, where and what you studied, what you earn, if you own a house on Facebook. According to the data you provide Facebook uses it to place a matching advertisement on your page.
Interest - It also tracks the interest you have like if you have interest in music, celebrities, publications, sports. It even tracks your friends' interests and find the way how it will be useful to place an advertisement matching to them.
Behavior - It uses the information about your loyalty cards, govt. data and marketing companies to track user behavior.
Apart from this, Facebook has huge data on your movements it also knows not only who you are but also where you go, If you have location on. It shows that if you own a bike and went on vacations or you are a gadget geek. It also gather information about your workplace, restaurant you visit and businesses you interact with. According to your status it shows the relationship your in or you have a breakup. It also tracks your online shopping behavior what you have shopped or not and what you have explored and put it in your cart but not purchased from its re-targeting tools. Facebook has a tool called pixel for its advertisers, the advertisers can put this code on their websites to track what people do after clicking an advertisement for the effectiveness of their advertisement.
So these are some of the ways the advertisers use the Facebook's information to target their audiences. There are many other ways they can use the information provided by Facebook. So, for some categories of people it is useful whereby it is also a breach to the privacy for some. Some people interested on being targeted by the sellers but some do not want any advertise on their pages. But the truth is that you are being watched by Facebook at every movement on the web.