Lists are one of Twitter's oldest features - introduced back in 2009 - but judging by my Twitter-using friends and colleagues, one of its least popular. I keep expecting Twitter to quietly deprecate lists, but as that has not happened at any point in the past decade it would seem lists are here to stay.
On the face of it, lists are very simple. Create a Twitter list and add other users to it. Go to that list at any time to see a stream of all tweets from users in that list. But why, really, would you want to do that? Here's one good reason.
If you have ever managed a Twitter account for a brand, you will know that there are accounts that you really have to follow for brand reasons. Perhaps they are are prominent figures in the industry, or sister brands with the same owners as you. Perhaps your brand or company even operates a 'follow back' policy of some sort.
But just because you should follow an account doesn't necessarily mean you want to see all their tweets, especially if they are a prolific tweeter or have some repetitive auto-tweeting nonsense in place. Pretty soon you could find your Twitter Home feed cluttered with junk.
Conversely, there might be accounts you are very interested in but really shouldn't follow. Perhaps they are competitors you want to keep an eye on, or brands you don't want associated with yours because they are controversial or inappropriate. What to do?
One solution here is to create a private Twitter list and add all the people you are genuinely interested in to that. You don't need to be following them, and because the list is private they won't even know of its existence, let alone the fact they have been added to it.
Then go ahead and follow anyone you feel you should for brand reasons. It doesn't matter if your Twitter Home feed gets cluttered up by these folks, because you can just go to your secret, private list at any time to catch up on tweets from those accounts you are genuinely interested in.