How does Facebook know what gift you like?

[carlos r]

I wanna send my friend a gift card for her birthday, and it says that she likes Starbucks on her homepage. How does Facebook know that? Is it just the computer randomly saying things or does she really like Starbucks?

And if so, how much should I put in the gift card?

[Robespierre]

They track everything you do and give all the info to NSA. They do their analysis and give the results to Facebook to tell you what you like based on things they already know you like.

[Josh]

She liked the 'Starbuck's' page on facebook, $20 dollars would be more than enough I would think.

[Thomas]

they read your private messages

[Asa]

Facebook tracks everything you do on facebook and based on that, it runs an analysis and guesses what you may like. This is just a analytic guess based on your behavior. It may or may not be correct.