For quite a while now, Twitter has lists. Lists are nice - you can include people with them, and then view their posting on a separate page. Or view multiple of these at once if you are using TweetDeck.
The process of managing lists leaves some to be desired, though - if you want to do something like
- Add all followed users to a list
- Exclude all followed users from a list
- Add all followers to a list
- Add all members from a list to other list
- Exclude all members of a list from another list
You are apparently expected to do so by using the little context menu on each user, picking "Add or remove from lists...", and then ticking/unticking the checkbox for the according list.