1.
Start with a black background.
Now type in the text you like to add this effect to with white color.
Right click the text and press break apart one time to seperate the letters.

Now right click each letter and convert them to seperate movie clips

3.
Select all the letters, right click and choose distrubute to layers.
Now in the layers panel delete the layer we started with, because its now empty.

Make a new keyframe at frame 5 and at frame 30, for all the layers.

5.
In frame 30 move the text all the way to the right, out of the stage.
Between frame 5 and frame 30 for all layers, right click and create motion tween.

6.
Now for all letters seperatly click at frame 5 and go to the properties panel and adjust the easing, for some letters set the easing to -100 and the rest at 100 and maybe one or two at 0.

Now the letters will not move at the same speed.

7.
At frame 30 for each letter go to the properties panel and adjust the alpha to 20 percent.

And now we are done, I just added a rectangle shape with not fill color, converted it to a movie clip, animated it by scaling it and put down the alpha just a with the text effect.