It looks to me like the way to attract a broader cross section of the world's cultures, which as far as I can see is a goal that is worth encouraging, would be for people to post information about songs, music, and other kinds of folk arts and traditions from other cultures when they find them.

It looks like one way people find this site is through Google searches. If the Mudcat turns up in someone's Google search on traditional songs from Mali, for instance, they might be enticed to stick around and post a few more. The only thing that would inhibit their being able to do so would be an inability to communicate in English.