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Information security
Information security

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1.1 Social networks

Comparing book and market value once again, the information collected by Facebook on their 1.23 billion monthly active users is worth almost a quarter of a trillion dollars (Wolfram Alpha, 2016b). This information includes some (apparently pretty tame stuff) you give when you sign up: your name, city of birth, city of residence, email address. Some you will give as a matter of course, such as relationship status, family members, birthday etc.

However, Facebook’s massive market value is the value to advertisers of the information you give up as you use Facebook to log your life. This includes what you’ve liked and disliked, which restaurants you’ve eaten at (so what foods you like), which sports teams you support (so which sports clothing you might like to buy), which videos you have watched (so which films you might like to buy) etc.

Print media – such as newspapers – once had a monopoly on ad-supported news. Because they printed only one version, in those days they used to say that half of every advertising budget was wasted, you just couldn’t know which half. Now, with Facebook, every advert that is placed in front of you is determined precisely by algorithms; algorithms that use what Facebook know about you to get the best bang-for-the-buck for an advertiser.

Activity 2: The value of information to Facebook

Given the following information about a Facebook user, what value could it have for targeting an advert?

  • websites visited
  • companies liked
  • their current mood
  • device they’ve accessed the internet from
  • their credit-card details


We came up with:

  • websites visited: Facebook could offer similar websites
  • companies liked: Facebook could offer competitors companies’ products
  • their current mood: Facebook could offer champagne adverts for a user who is celebrating, or man-size tissues to those who are unhappy
  • device they’ve accessed the internet from: Facebook know what mobile phone you have and so could offer games for that phone
  • their credit-card details: Facebook could offer special services for competing credit cards, with special cash-back deals.