Here's a step-by-step solution for dynamic meta tags inside each thread:
1. open /template/default/view.php
2. anywhere after ' if ($badwords == "true"

{}' paste:
[code:1]if (!$fmessage->parent) {
$metapost = preg_replace("/[^a-z .A-Z0-9s]/", "",
strip_tags(substr($fmessage->message,0,400)));
$metasubj = preg_replace("/[^a-z .A-Z0-9s]/", "", $fmessage->subject);
$metadesc = $metasubj . ' - ' . $metapost;
$mainframe->addMetaTag( 'description' , $metadesc );
$keyarray = explode (' ' , $metasubj . ' ' . $metapost);
$search_ignore = array();
@include "$mosConfig_absolute_path/language/$mosConfig_lang.ignore.php";
foreach ($keyarray as $keytest) {
$keytest = str_replace('.' , '', strtolower(trim($keytest)));
if ($keytest && !in_array( $keytest, $search_ignore ))
$metakey .= $keytest . ', ';
}
if ($metakey)
$mainframe->addMetaTag( 'keywords' , substr ($metakey, 0, -2));
}[/code:1]
3. To remove the generic Joomla meta-tags from appearing after the dynamic tags, enter /includes/joomla.php, find and comment out the existing function appendMetaTag() and paste the code inside the Meta Tags Mod zipped attachment. (Bb-code chews it up if I paste it here.)
4. To improve keyword filtering, replace the existing /languages/english.ignore.php with the version I posted further down in this thread. Note that this would also enable your default Joomla/Mambo search component to ignore a list of common English words.
Here's an example of a [url=http://www.gossper.com/component/option,com_fireboard/Itemid,26/func,view/id,253/catid,27/]thread[/url] on my site that uses this mod.
Comments and suggestions welcome!
Gom
[url=http://www.gossper.com/welcome]Gossper[/url] - The Last Social Forum [file name=Meta_Tags_Mod-f105129ed3a70433e5cc182132fec7bc.zip size=897]http://www.bestofjoomla.com/images/fbfiles/files/Meta_Tags_Mod-f105129ed3a70433e5cc182132fec7bc.zip[/file]