The following 'Blogger Status' announcement appeared late last night (UK time).
Tuesday, January 19, 2010
Users are experiencing problems playing videos in Blogger blogs. We are investigating and will send an update when fixed.
Visitors can check the current situation by clicking on the Blogger Status link above.
Meanwhile, I'm sorry that no one will be able to see any of the videos (other than the embedded ones) until Google/Blogger get their act together, and hope that you'll return once the problem has been resolved - which I'll post on Twitter in due course.
And, if you're thinking about starting a blog and can't decide between Blogger and Wordpress, this depressing news is yet another reason why you should chose the latter, and why some of us are planning to migrate there from Blogger.