Flickr's UI change is definitely polarizing, mainly due to the fact that is so sudden and all encompassing. Considering what Yahoo has to prove in the coming months and years, it's probably a good move on their part, mainly because after so much stagnation with this product, any movement is good movement. If the reaction to the UI is overwhelmingly negative, they can course correct. Right now though, they need to show movement of any kind, and they chose to do it in one of the most visual ways possible.

I look forward to seeing if this change proves to be more than skin deep.