[Amenadiel]

it does work fine on my 3.6.8 PL2, and yes, each forum keywords spread to every thread under it.

I'd like to find out, however, how to avoid adding default keywords when a forum has its own set.

EDIT: spoke too soon. I used this on my headinclude template:

<if condition="!empty($foruminfo[forumkeywords])">
<meta name="keywords" content="$foruminfo[forumkeywords],$threadinfo[title]" />
<else />
<meta name="keywords" content="$threadinfo[title], $vboptions[keywords]" />
</if>

and

<if condition="!empty($foruminfo[forumkeywords])">
<meta name="keywords" content="$foruminfo[forumkeywords],$foruminfo[title_clean]" />
<else />
<meta name="keywords" content="$foruminfo[title_clean], $vboptions[keywords]" />
</if>