Having a larger tag cloud available to choose from when adding new bookmarks would help allow users to create their own controlled vocabulary of tags. Entering tags manually and with no visual reminder of previously created tags (starting with other letters) leads to creation of multiple tags to describe similar concepts. Would love Diigo to look at and consider using system used in Shelfari to tag bookmarks. Shalfari gives clickable, alphabetical cloud of your previously used tags and separate cloud of user generated tags that may apply. It is ridiculously easy to develop an organized tagging system!