What makes a song a “shoutin’ song”?

Last night, I was talking with a friend who loves Southern Gospel but is well off the beaten path of the heart of this genre’s circuit. As I was trying to describe that unique breed of song known as a “shoutin’ song,” it occurred to me that we might arrive at a better description with a collective exercise.

First, for other readers off of the beaten path, here are a few examples of local and regional groups singing “shoutin’ songs”:

• Fletcher Family – “Better Farther On“
• Primitive Quartet – “Gloryland“
• Perrys – “Did I Mention“

These songs share a few common characteristics:

• They are slow
• …but they aren’t big ballads – they hold the same dynamic intensity throughout, as opposed to starting low and slow and building to a big, slow ending
• They’re either about salvation or Heaven (or both)
• They’re delivered passionately, and to the right audience
• There is, at least, an a cappella encore (but is this an intrinsic characteristic or a coincidence with these three?)

What other characteristics make a song a “shoutin’ song”?