Dumb Question: Using maillist summaries - how to reply to particular posting?

[Herschel]

I apologize if this is in the FAQ; I just rechecked it and I do not see
it mentioned.

Summaries have at least 10 (or more postings) I would like to keep my
reply on the same thread both for coherence and to aid others having
similar problems later.

Another question (that is not to be taken in too snide a tone) why is
the Red Hat search so worthless?  I do better greping on the stored
summaries in my email or with Google than right on the list.

TIA