I guess the YouTube phenomenon was a give-away. But I hadn't thought about it much. I have noticed that I've been watching a lot more talks.
Google has lots of talks such as Google Tech Talks and more Google TechTalks.
The IBM Almaden Institute has made its talks available: Cognitive computing and Comlexity.
TED has made its talks available.
Here's Linus Torvolds on GIT, his new SCM system. Even though this talk was given at Google it is posted on YouTube and not on Google TechTalks.
Here are Authors@Google.
I just came across a startup site that has advice in simple video segments about how to live your life. Here's one on giving your cat medicine.
Most of us find it much easier to watch a video than to read text.