What is up songs that have a background chorus/singer going "Ooohh whoOOoa!, Ooohh whoOOoa!"?

Some examples of songs that do this are:

Kings of Leon – Use Somebody (Check out the lyrics to see what I mean)
Three Days Grace – Break
Lady GaGa – Bad Romance

What is it with having background singers saying “WooOoohha” or “OOooOoohh” while the music plays and the lead singer sings? Does it add to the song in hopes of making it awesomer? Do you think it’s cool or more of a distraction?

What are some other songs that do this? What are some other things artists add to their music to enhance it?