Twitter has begun rolling out its latest feature, Lists, to its user base at large.
The basic idea behind the feature is that it lets Twitter users group the people they're following into arbitrary lists. Then, if they only want to read updates from a certain subset of those people - say the news feeds they follow, or the staff of a certain publication - they just click on the list in question and they're presented with just tweets from those people.
Lists can be either private or public, which allows Twitter users to view other users' list and even subscribe to those tweets without having to subscribe to the individual users. That means they can have a private "Family" list, for example, and a public "Celebrities" list.
Right now, adding people to lists is somewhat of a time-consuming process, requiring users to either search for individual users to add to it, skim through the list of people who are being followed, or add people from their own Twitter page. Likewise, the list functionality sometimes feels a bit bolted on; it's not fully pervasive yet, but that will probably come with time.
Previously in testing for a limited number of users, Lists has begun rolling out to larger and larger chunks of the Twitter community. At the moment, no third-party clients support Lists.