Serenading?

[Aerylle]

First off, this is probably the wrong place to ask this, and I know this. I am asking it here however because I don't know where it would go. Anyone know where this should go? Thanks.

Second, what exactly is Serenading other than dressing up and singing for Fraternities? Or Fraternities singing for the girls, obviously.

But, what does it accomplish?
Why is it done?
Who does it? - The pledges only, or the entire chapter?
How often is it done?

As you can see I'm very "green" so to speak on nearly every aspect of Greek life and as I am Rushing this fall, I am curious as to what this term means.