This is great but Flickr slideshows don't appear to be supported by groups (please correct me if I missed it!). This is a curious omission given the orthogonality of the system (i.e. most anything you can do with sets you can do with groups so it doesn't make any sense to me that groups don't have slideshows but sets do).
You can now view slideshows of just about any group of photos that you can think of: your photosets, your own personal tags, global tags (such as the one above, using the "flower" tag) and your favorites. You can adjust the speed of the slideshows, and click on any image to visit its photo page. You can start the slideshow from the photoset, tag and favorites pages. And they each have their own URL ( /show/ on the end of the URL), so it's easy to copy the link and send to your friends.