I like structuring things. I like folders, lists, categories, labels, you name it. Twitter has the ability to group your contacts into lists, but that is not something they advertise very clearly. The Twitter website as well as most of the clients offer a limited user experience to managing lists, if they implement the feature at all. You can do it, but it is tedious and very easy to miss something. There is not a single view to show you all your contacts along with their group membership. Luckily for people like me, the web is filled with clever people who know just how to create solutions for this. Look at this:
I edited the image to show you the top and bottom of the screen in a single view (hence the grey line in the middle). What it does is pretty obvious: it shows all your Twitter connections along with your list, to give you a single overview of all contacts, all groups and all memberships. Edit away, click "save changes" and you are done! Great stuff.