Marcus Leon
Marcus Leon

Reputation: 56699

How do sites know who my Facebook friends are?

When I went to Spotify.com for the first time, I saw "Spotify is used by these Facebook friends of yours: ...". How does this work?

I had thought that cookies sent from domain A (ie: Facebook) were not included in HTTP requests to other domains (ie: Spotify). Is this not so?

If Spotify could access Facebook cookies to determine my identiy then it makes sense that Spotify could connect to Facebook to query this data. I just thought this wasn't possible.

Upvotes: 0

Views: 212

Answers (1)

Niet the Dark Absol
Niet the Dark Absol

Reputation: 324750

Spotify places an iframe on their page, which contains a page on Facebook and is passed some parameters in the query string. Facebook then reads the parameters, gets the Facebook cookies your browser sends, puts them together and tells you who your friends are.

Upvotes: 3

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