LordOfUltima sent over a pair of videos demonstrating how to set up Akuma's 'Vortex' metagame in Street Fighter 4. While this tutorial focuses on Akuma, some of the tactics, like untechable knockdowns and safe-jumping, apply to the rest of the cast.
Here's a little more background on what this is.
"The Vortex" is another name for Akuma/Gouki's wake-up mixup metagame. While most characters have this as well, Akuma's is special in that he has a staggering amount of options, and most of them are relatively safe. I think that's reason enough for it to have its own name, and so did Arturo Sanchez, who is said to have coined the term itself.
Untechable knockdowns are what you're going to want to use to start up and continue the Vortex, as it leaves your opponent in a large guessing game where percentages are not in their favor. The objective is to keep making your enemy guess wrong every time the get up off the ground, and then knocking them down to start it all over again.
