If you ever include a YouTube video in your blog, or on a website, it's a really good idea to SAVE IT LOCALLY! Keep a copy in your own stash, that is.
Here's a basic article that tells you how to do it manually. With some searching, you can find more tools to help automate the process.
Why do you need to save videos locally?
Because a good percentage of videos get taken down eventually. It's intolerably high if you like your blog content to be useful and relevant for more than a few weeks.
This is especially true if you link to videos that were captured off TV.
If anybody knows if there's a Wordpress plugin to automatically copy videos locally somehow, I'd love to hear about it.