I have some sites which have been running for a long while, and due to not having time on my part to upgrade them they still run pretty old scripts with custom coding ( If it aint broke dont fix it 
). Some time back i realized the rel=”nofollow” thing and how people posting links on those sites got Backlinks for free. After doing a little backlink checking i found that my sites were linking to competitor sites , which is totaly unacceptable.Also with so maybe free backlinks going out PR can be affected ( am not shore about that though ). So with a few lines of PHP you can kill all free back links people have been getting through ur side.
So if you are stuck with the same situation here is a little help , Assuming your site is running in php. What we do is buffer all the content and find all non site links and replace them with a additional nofollow tag.
// Your sites code goes here
$content = ob_get_contents();
@ob_end_clean();
preg_match_all(‘!href[\s]*=[\s]*["\']{1}([\w]+?://[\w#$%&~/.\-;:=,?@\[\]+]*)["\']{1}!’,$content,$matches);
// Replace all outbound links with nofollow
$replaced = array();
for($i=0;$i<count($matches[0]);$i++)
{
if(strstr($matches[1][$i],’http://www.sitename.com’)) continue;
if(strstr($matches[1][$i],’http://sitename.com’)) continue;
if(in_array($matches[0][$i],$replaced))continue;
$content = str_replace($matches[0][$i],$matches[0][$i].’ rel=”nofollow”‘,$content);
$replaced[] = $matches[0][$i];
}
echo $content;
Now i hope this code increases the PR for the sites , they are PR 5 for now … will post results if i see any changes in the site stats.
I noticed that after implementing this code, on some links it inputs the tag twice… have you encountered this?
Hi, Just supposed I’d let you recognize your blog is rendering funny in my K-melleon browser. Looks good from what I can see however.