[kh99]

I think something like this works for the query:

SELECT COUNT(*) AS count FROM thread WHERE postuserid = id AND forumid IN(1, 2)

So I guess you'd want something like:

$count = $vbulletin->db->query_first("SELECT COUNT(*) AS count
                                                      FROM ".TABLE_PREFIX."thread 
                                                      WHERE postuserid = $vbulletin->userinfo[userid] AND
                                                           forumid IN(1, 2, 3)");

And the result would be in $count['count'].

Where to put it is another question, it looks like the HTML for those blocks is generated in member.php around line 474, and there's a member_build_blocks_start hook right before that, so maybe that's a good place.