Wikipedia, today he added Commons to it as well. Commons is essentially different in that there is only one link to Commons per concept.
When you look for pictures of a horse at Google or Bing, it makes a big difference in what language you are looking for that animal. If you look for instance for an "សេះ" you will find far fewer horses.
This is what it looks like in Arabic. As there is an annotation referring to the Arabic Wikipedia article, the Arabic article is selected.