This can be quite difficult for newcomers. There are simply too many posts to look back through.

I would suggest that you do a quick check to see if there is a recent discussion on the subject by using the Search in the information bar at the top of the page.

Just to make things confusing there are two "search" mechanisms. The one at the bottom relates to all of AWAD. You need the one at the top, below the AWADtalk heading.

Chose the options highlighted in red:

Forum to search
All Forums
Words to search for
your word here
Search options
Entire Phrase or alternative, if you prefer
Date Range
All posts
Number of results to show per page.

If it doesn't give you anything, modify your word and search again. If you can't find anything useful, then it is likely to be new.

If you do find some discussion decide:
(i) Is it recent?
If it is, you may choose to add to the thread which you have just uncovered.
(ii) Is it old?
If it is quite old, then some people may not have been around the last time it was discussed. If the thread is short, it may be a good idea to add your post, it will then "resurrect" the thread to the top of the list and people can follow on from there. If it is very long and has divided into a lot of subthreads, then you might prefer to start a new thread. If you are feeling helpful you can provide a link to the old thread using the method shown on this page.

Providing a link to an old post:
Once you have conquered adding links - see using markup in posts, use the same method to make an internal link.
(i) find the relevant post, using "search" or however you prefer.
(ii) Highlight the post address from the window at the top of your screen then copy and paste it into the new post, deleting everything after the number:

http://wordsmith.org/board/showthreaded.pl?Cat=&Board=words&Number=17010

adding [ url ] before and [ /url ] after (take out the extra spaces) makes it into a hot link. So I get http://wordsmith.org/board/showthreaded.pl?Cat=&Board=words&Number=17010 and others can choose to look at it.

Postscript:
Sometimes old threads become difficult to follow in flat mode, they seem to have a mind of their own, you may need to use threaded moded which you can either change thread by thread (see the icon to the top right of your screen, once you have a thread open) or in your profile.

Wide Links There has been some discussion of w-i-d-e mode. This happens when a thread, for no apparent reason, takes off into the blue yonder to the right of the screen. It is a lovable/irritating feature of this bulletin board and takes place when some kindly soul adds a very long URL. It changes the width of every post in the thread. If you spot this has happened, the easiest thing to so is go back to your post and either delete the link or take out the "(square bracket)url(square bracket)" "(square bracket)/url"(square bracket)" which turns it into a hot link and let people post it into their internet-browser-of-choice themselves. No-one else can edit your post, so you may find a private message from someone who has noticed the thread go w-i-d-e, asking you to change it.