assiging/managing folders to a feed is not the best experience and can be easily improved with a few tweaks:
1) when user selects the folder to assign the feed to from pull down menu the pull down disappears. Most of the time, I want to assign the feed to multiple folders so this an annoyance.
2) sometimes the vertical scroller does not appear in the pull down menu. this seems to be a bug. I have a lot of folders and when this happens I cannot get to all of them so I have to close the pull down menu and re-open, hoping that the scrolling appears. Support details here, http://bit.ly/133n8Ch
3) the width of the pull-down prevents the full folder name from being viewed. like-wise, there is no hint/alt text on hover. So, if a user has a bunch of folders with the same prefix it is impossible (or atleast cumbersome) to see which is which. For instance, I have a bunch of folders that start with "economic development...". I can't tell them apart in the menu.

Of course the last issue can be resolved easily by me if I change folder names. But, it is a UX shortcoming nonetheless that you may want to address at some point...