[#wikichng | wiki artifact].

The <b>Z</b> card is the required checksum over the rest of the artifact.

<a name="forum"></a>
<h3>2.8 Forum Posts</h3>

Forum posts are intended as a mechanism for users and developers to 
discuss a project.  Forum posts are like messages on a mailing list.

The following cards are allowed on an forum post artifact:

<blockquote>
<b>D</b> <i>time-and-date-stamp</i><br />
<b>G</b> <i>thread-root</i><br />
<b>H</b> <i>thread-title</i><br />
<b>I</b> <i>in-reply-to</i><br />
<b>N</b> <i>mimetype</i><br />
<b>P</b> <i>parent-artifact-id</i><br />
<b>U</b> <i>user-name</i><br />
<b>W</b> <i>size</i> <b>\n</b> <i>text</i> <b>\n</b><br />
<b>Z</b> <i>checksum</i>
</blockquote>

Every forum post must have either one <b>I</b> card and one <b>G</b> card
or one <b>H</b> card.  
Forum posts are organized into topic threads.  The initial
post for a thread (the root post) has an <b>H</b> card giving the title or
subject for that thread.  The argument to the <b>H</b> card is a string
in the same format as a comment string in a <b>C</b> card.
All follow-up posts have an <b>I</b> card that
indicates which prior post in the same thread the current forum
post is replying to, and a <b>G</b> card specifying the root post for