Well, they already make trailers and put them to every videosharing site possible.
If you add all footage from the trailers, it can be about 10 minutes, maybe more.
If you add all footage from the trailers, it can be about 10 minutes, maybe more.
You could presumably then tailor trailers to particular groups to emphasise desired attributes.
Downside to that is that if you sit through a few trailers you could literally have seen a-third of the movie before you go to watch it.
I enjoy movies orders of magnitude more now not already having seen the set piece scenes / heard the important lines.
If you have seen the movie True Grit - either the old or the new one - compare the trailer to the 1969 version, which essentially gives out all the plotpoints - http://www.youtube.com/watch?v=tN-j4GDqjv4 - and the trailer to the 2010 version - http://www.youtube.com/watch?v=CUiCu-zuAgM .