One of the biggest complaints I get about my search videos is that I talk way too fast. I get that complaint in general about the way I talk, but when you have thousands of views on each video, I know I should slow down. When I speak publicly, I tend to slow down but when it comes to speaking one-on-one and producing these weekly videos, I speak like a New Yorker (I am a New Yorker).
That being said, YouTube now has a solution for that. They've quietly added a slow motion feature to the Video Editor and Enhancements tools. Okay, it might make me sound ridiculous but it can be fun to play with. Of course, most basic video editing tools, like iMovie and others, have a slow motion feature. But as YouTube grows, video editing via your browser is something they want to do.
On the Enhancements page, click the turtle icon next to "Stabilize" and pick your speed.
In an Editor project, click the effects icon and check the "Slow motion" box.
Forum discussion at YouTube Help.