The following marks mark articles as (kinda) unread, in one form or other.
gnus-ticked-mark).
Ticked articles are articles that will remain
visible always. If you see an article that you find
interesting, or you want to put off reading it, or replying
to it, until sometime later, you'd typically tick it.
However, articles can be expired (from news servers by the
news server software, Gnus itself never expires ticked
messages), so if you want to keep an article forever, you'll
have to make it persistent (see Persistent
Articles).
gnus-dormant-mark).
Dormant articles will only appear in the
summary buffer if there are followups to it. If you want to
see them even if they don't have followups, you can use the
/ D command (see Limiting). Otherwise (except for
the visibility issue), they are just like ticked
messages.
gnus-unread-mark).
Unread articles are articles that haven't been read at all yet.