Twitter lists: why?
Twitter provides you with the ability to create special Twitter Lists of your own that you can use (and others can follow). You can also follow Twitter Lists other people create. Why in the world with all else you have to do would you want to create a Twitter List?
Good question. Depends on whether you want an easy way to group people you follow into one place. (I mean their tweets.) As your list of followers grow, your Twitter List(s) help you follow a select few whose latest tweets you’d like to easily find and review when you have time.
Since Twitter can explain better than I can, you can find more here:
[Article updated in 2020]