Henry, I read your first message again and believe there could be some confusion about using the words "thread" versus "post" or "posting". You seem to use the word "thread" for both "thread" and "post", which probably did not give you the answer you were looking for.
- A thread is a sequence of messages.)
- A post is a message in a thread (e.g. the initial message and replies or replies to replies).
Both of them can be accessed via Uniform Resource Identifiers (URI) which in the early days of the World Wide Web (WWW) were refered to as URLs (Uniform Resource Locators). For the purpose of this discussion about AlfaBB, we can assume that URIs and URLs are the same. In other environments, they may differ (e.g. when the same resource exists at multiple, individually addressable locations).
Anyhow, an URL for a thread looks like this:
New Author and Thread Preview?!
...while an URL to view a single post looks like that:
www.alfabb.com/bb/forums/showpost.php?p=124805
If you get an URL for viewing a single post, you should also see the thread it belongs to in the top right corner of your browser window. Although it doesn't show it as an URL, you should be able to click on the text string to see the whole thread.