Fewer people will be looking to answer questions that appear
to have already been answered, that is true. But there are so
many people that can answer questions that it won't really
matter to you. Basically every question and answer is looked
at by many people (verified if prefer), so if you post to your
original thread you are almost certain to continue.
Starting another thread elsewhere is generally a very bad idea,
if for nothing else than the annoyance factor of asking a question
that was already asked and possibly answered by the time
someone else sees it in the other thread.. Even more annoying than finding
a question already answered after spending a long time to answer
is to find that an earlier answer in another thread was better, or
was correct and that your answer was both wrong and the question
misread.
By sticking to a thread everyone has the benefit of the earlier
answers and doen't need to keep getting more detail.
Incidentally this would have been the better newsgroup, but
once you start a thread stick to it. Most people look at several
newsgroups and almost everyone answering questions is looking at
excel.misc, excel.worksheet.functions, and excel.programming.
http://www.mvps.org/dmcritchie/excel/xlnews.htm
So even if you posted to wrong newsgroup, you would get an
answer. Also look at the reference for using newsgroup archives,
because practically any question you would ask has already been
answered (some assembly may be required).
Those that have very specialized questions may be posting in
much more specialized newsgroups. If in doubt the best place
to post is excel.misc which is for general questions.
