A message or post is the smallest unit in a discussion.  A threaded discussion (or thread) is a series of posts related to the same topic or subject.

A post's layout can be set using the Nested/Flat link in a VoxForge forum (located on the top right hand corner of a thread) and can be:

• flat - posts appear one after another;
• nested - posts are grouped in tree-like structure.  Messages are usually grouped visually in a hierarchy by topic. A set of messages grouped in this way is called a topic thread or simply "thread".  New posts do not necessarily appear at the end of the discussion thread but appear under the post that is being replied;

Flat/nested choice often determines the way people discuss. In the flat layout there is only one "path" - that is why it is sometimes called "linear".

Nested layout offers more freedom, more digressions and more paths in the discussion but it is more difficult to spot new posts (unless you use RSS feed or watch the thread).