These are topics in Zulip. Async usage for me looks like:

    1) Skim list of Streams in the org, streams show 
    the number of new messages in a bubble next to the name

    2) Click on the Streams relevant to me to expand 
    the list of Topics with new messages 

    3) Skim the active Topics to see which are relevant 
    to me and click into each of those to skim new 
    messages and reply if necessary 

    4) Feel good knowing I've caught up on everything 
    relevant to me without needing to see the thousands 
    of other messages in the org

    5) Click the dropdown for each Stream and select "mark
    all messages as read" so I'm back to the equivalent of
    inbox zero and can repeat the process later.