Update: It seems like Google Reader is showing embedded Flickr Videos, for me at least. I inserted a picture below showing the Flickr Video in this post, rendering in my Google Reader (on Apple Safari).
A Google Groups thread has word from a Google representative, Roger from the Google Reader team, that Flickr Video will soon be supported in Google Reader.
For example, if you are using an RSS reader, you might not be able to see the embedded Flickr video below this line:
But soon, if you are using Google Reader, you will be able to see embedded Flickr Videos - like you can see embedded YouTube or Google Video videos.
Roger of Google said:
Thanks for reporting this. We're currently working with Flickr to get Flickr videos to embed properly when viewed in Reader. We should be able to straighten it out shortly. Thanks for your patience!
Flickr first launched 90-second video clips on the night of April 9th.
Forum discussion at Google Groups.