@mmasnick Lists are indeed great.
But they're not especially good at topical sorting. People tend to be multidimensional, and don't simply post on single topics.
(There are some exceptions. But they're ... exceptions. And yes you can use topical lists for them.)
You also cannot post to a specific list --- these aren't groups or channels. They're specifically a way for you to organise your incoming stream(s).
What I find most useful is to arrange lists by interest level. I usually sort this to about three levels, high medium and low-level interest. I'll also usually dump high-frequency posters into a "Voluble" list --- they can fight amongst one another for attention, and not drown out the quiet-but-interesting types.
My higher-interest lists I curate aggressively, and if someone's not providing joy or is posting excessively I'll bump them down a level. In practice, 15--30 people in my highest-interest list seems to work out about right, and that's including a number of older accounts which seem to have gone mostly inactive. Less is more.
Note that in the standard Mastodon interface, you can edit lists either:
From a profile page, under the kebab menu, "Add or Remove from Lists", or
From a List stream itself, burger -> "Edit List".