Twitter's new Lists feature is finally rolling out to everyone. This feature has been in limited testing for a while and it's good to finally be let inside the candy store. My nose was getting cold from pressing against the glass watching all the cool kids have fun with their Lists. In case you haven't played around with them yet, Lists are similar to the Groups feature that many clients already have, but in some ways better.
There are two ways to use Lists: create your own or follow someone else's. If you create your own you can tag it as Private or Public, depending on if you want to allow others to follow your list. Once you create a list you can either search for users to add to it, or page through the list of people you're following and add them from there. The latter technique requires a lot of patience just because twitter can be so slow in serving up pages of followers.
Following someone else's list is as simple as going to the list's page and clicking the 'Follow this List' button. The challenging part is finding the list in the first place. Twitter search doesn't yet appear to be searching for Lists. I've found Lists so far by seeing people tweet about them, by checking the new "Listed" metric on my twitter profile page (which shows how many lists you're on, and allows you to click through to a list of those lists), or by checking the 3rd party Listorious site, which is trying to become a go-to directory of Lists.
Now here's the secret ingredient that makes Lists really interesting. When you follow a list, you follow the list and not the users on that list. This extends to lists you create. You can add someone to one of your own lists without following them. This makes the Lists feature better (in my opinion) than the Groups feature that a lot of Twitter clients offer. Your 'main' tweet stream won't get junked up with all the people on all the lists you follow. If you have a temporary interest in a topic (say there's a big hoax about a kid floating away in a balloon, to make up an absurd example) you can follow (or create) a list devoted to that topic, read it for a few days and then unfollow it and not wind up having to sort through your Following list to clean those people out of your tweet-stream.
Of course this has its down side too. It means that, for now at least, lists are really only useful if you do all your twittering from twitter.com; as far as I'm aware none of the popular Twitter clients support the feature yet (I'd be overjoyed if someone proves me wrong in the comments). And some users might want to follow everyone on a list, so ideally, Twitter should offer that option. I'd also love to be able to 'hide' particular users on a list (one belonging to someone else) I'm following, or alternatively let me clone another user's list so I can make my own additions and subtractions to it. Some Twitterers are just a tad too enthusiastic (aka spammy) for me to want to listen to them.
I'm sure the Twitter devteam is thinking about ways to improve Lists, and I'm sure there are client programmers working on ways to automate features that Twitter isn't officially offering yet. Lists seems like it'll be a very useful feature once it's had time to mature a bit. If you don't have Lists on your twitter account yet, you should have it in the very near future. Keep checking twitter.com.