Porting a subwoofer box?

[Hair]

I'm totally stupid when it comes to stereo stuff, so help me out here please.

I thought that porting was something that you did to a subwoofer box when you couldn't make the box big enough for the required cubic feet needed, so then you made it as big as possible and then ported it. Is that even close to being right?

So what is the reason for a port in the first place?

Are ported boxes better than sealed ones?

When do you need to port a box?

What size ports do you make?

How should a port be made... just a hole in the side of the box??

As I look at woofers in the catalogs they say like 1 to 3 cubic feet required... well what is it... 1 or 3?? One size has to be better than the other.

I know these are probably basic questions for you "system" guys. Please help.