How is this type transition done?

Does anyone know how the fading text transition is done like the subheads in this ad(“for someone else to…”)? I could replicate it by making each word a movie clip, but it seems that there must be an easier (or at least more efficient) way. I’d also like to do it for a vertically oriented list from top down. Can anyone point me in the right direction? Thanks!

http://www.progrphx.com/type-trans.html