I you have my back! ZERO-DEGREES of!
I like back bacon.
As far as facebook goes, the point of 6 degrees is a hypothetical favor network. A friend is someone you can aska fvor from. maybe a small favor like an introduction. that's why the concept of degrees of separation makes sense. Facebook freinds are not freinds. In some case facbook can be useful for tracing the spread of social disease however.