I am not sure about what the link farm is. Especially after I visit some websites of Yahoo or Kijiji on different countries. Each different country homepage of Yahoo or kijiji puts links to the other country websites as UK Canada Ireland Hong Kong Japan China.... Are they linking to each other as link farm?
They do country specific url's to rank better in the specific countries. Also separating country url's also makes it easier to separate different languages and such. For example, in the US if someone posted something in french, less than 1% of all people would understand it.
kijiji is a good source of traffic for my site. There is no direct linking allowed, but it does keep track of the views to your ad.