Brand new in Yummy 2.0 is the ability to browse through your bookmarks by tag. You could already search for them but a number of users indicated that a screen like this would be very useful:
From here you can drill down to get a list of bookmarks.
One neat touch here (if I do say so myself) is that pressing “Add” button pre-populates the tags field with the current tag, so in this case the “Add bookmark” screen would have “iphone” in the tag field.