There are hundreds of Twitter clients, gadgets and widgets out there, but most of them want your username and password -- a potential hurdle if you're privacy-minded. But there are ways of enhancing the Twitter experience without giving up your personal details.
At the TwiTip blog, guest poster Alexander rounds up 11 Twitter tools that don't require a password, sorted into categories like statistics, discovery and who's following (or unfollowing you). Perhaps the most useful in productivity terms is Tweetwasters, which tells you how much time you spend on Twitter. (My total Twitter posting time is estimated at less than a day, though of course that doesn't factor in reading other people's tweets.)