A very important fact that seems to be getting little to no coverage at the moment about Twitter Lists is the issue of namespaces. Twitter's number one asset is its control and allocation of namespaces. Those little things we call 'Usernames'. @chrissaad is not just my Twitter Name, it is a short form addressable identity that concretely links to my Twitter inbox any time someone uses it in a Tweet.
Addressable, convenient namespaces that can be used in a sentence like this are so interesting and important that facebook went to great lengths to copy them. Nothing on the open web has yet come close to this simplicity and effectiveness. Which is not to say there won't be an alternative soon.
The important fact with Twitter usernames, though, is that they are unique. There is a finite and shared 'space' in which 'names' can be allocated.
The result is that early adopters end up with all the best names and squatters rush to lock up all the best phrases. Late comers to the system end up with names like chris2423.
Twitter Lists, however, are different. They include the list creator's username. For example my JS-Kit list is "@ChrisSaad/jskit".
As you can see, the list 'JSKIT' is attached to my username. This means means that each user has their own namespace.
This result: There can't be a landrush for List names because the list naming convention sits on top of the username. It also means that no one can own a definitive list on a subject because each list is subjective.
This is an important design decision for Twitter. One that has both pros and cons for the community. Overall, however, I think the decision was a correct one. Lists can rise and fall organically (or at least based on the influence and popularity of their creators) without the pain and pressure (for Twitter) of maintaining yet another shared namespace.
Twitter's username namespace, however, is just rife with and waiting for all sorts of headaches. I don't envy their position and I can't wait for an open alternative.