Facebook is Free But How Facebook Earns... ? | Facebook Earning sources

Hello friends
   Many people are ask me that facebook is free for us so how facebook company earns money?
So please read this article and i'll give answer of your questions. When we create a facebook profile, we writes our many information in our facebook profile as name, college name, company name, standard, family person etc. and we start surf facebook. Facebook stores our information in database and use that data for display ads. As we create a facebook profile and we set our profile as a engineering student. Then facebook observe that we are a engineering student. when we surf facebook then we saw some ads related to our study or institute or colleges. Many colleges or institutes create a ad for promote their college or institute and they give some money for facebook. Facebook use our data and check this we are a student of engineering so facebook display ads of those colleges or institutes.

 As we saw a picture of facebook profile, picture shows the ads for facebook users. Thus facebook is earn by normal users who use facebook. 

Facebook is know our many private details. As we go to a laptop shop for visit any laptop and we use their facebook for sometime than facebook observe that we are in the laptop shop. After sometime when we back to home and if we use facebook, we saw that some ads are displaying in our screen which is related to laptop. Thus facebook earn by those companies who needs  to promote their laptop company.