driveshaft ?

So I was doing some online 'window browsing' looking at plenty of stuff that I can't afford and I was looking at cf driveshafts. And I realized I have no idea what are the advantages/purpose between a 1pc and 2pc driveshaft....I even want to say that I remember hearing of a 3pc for our cars. So whats the purpose of splitting them into more than 1pc?

Some people were reporting vibration problems with the 1 piece because our driveshafts are longer than just about any other cars. The 2 piece eliminates this problem. The 1 piece is by far better though. Our stock driveshaft is 3 pieces, the 1 piece replaces the whole thing and is 13 lbs, the 2 piece only replaces 2 of the sections.and weights slightly more plus the weight of the 3rd piece of the original.

Ah, makes sense, thanx