How does facebook select 'suggested pages'?

[Terry]

How does facebook choose which 'suggested pages' to put into your timeline. I seem to keep getting some dodgy 'local sl*gs uk' site as a suggested page and also gambling sites which I'm not too happy about

[Jonas Laursen]

Many of today's large Internet companies like google and Facebook install cookies on your computer that traces what pages are visited on the computer.

Facebooks suggested pages are properly mainly from the pages you liked already on Facebook, and the statuses you make, and pages you visit, or anyone else visits on the computer.

Check with other people who uses the computer, maybe it's taking in info from sites they visit.