[renemark]

AdminCP > vBulletin Options > Search Engine Friendly Archive. Click Yes and No in the two first radio buttons.

FTP to your forum root and edit /archive/index.php. Go line 391, replace this code:

PHP Code:

$output .= "\t<li>$thread[prefix_plain_html] <a href=\"" . $vbulletin->options['bburl'] . '/archive/index.php' . (SLASH_METHOD ? '/' : '?') . "t-$thread[threadid].html" . ARCHIVE_SESSION_URL . "\">$thread[title]</a>" . iif($pda, " <i>(" . construct_phrase($vbphrase['x_replies'], $thread['replycount']) . ")</i>") . "</li>\n"; 


with this

PHP Code:

$output .= "\t<li>$thread[prefix_plain_html] <a href=\"/" . "showthread.php?t=" . $thread[threadid] . "\">$thread[title]</a>" . iif($pda, " <i>(" . construct_phrase($vbphrase['x_replies'], $thread['replycount']) . ")</i>") . "</li>\n"; 


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It's beyond my knowledge how a popular forum software in 2011 does not handle SEO correctly. If we look past more complicated problems like lots of duplicate content problems within the forum, it's even more strange how vBulletin actually made the old v3.8 archive worse when it comes to SEO.

This hack makes your archive a search engine friendly html sitemap. It passes Pagerank from your homepage to your subpages, which is very important. A XML-sitemap doesn't do that, and threads buried deep in your forums will never rank high as search engines like Google can't see any connection with the rest of your site.