This isn’t a plugin, it’s a ‘hack’ but I can’t think of where else to put this.
I have blog posts (duh) and I have forum topics that, sometimes, relate. I wanted to have a way to relate the blog posts to say ‘Comment here’ and ‘Forum chat here.’
The solution is stupid easy. I made a custom field in my blog (forum_topic) and then added this to the link with my comments link:
<?php $forum= get_post_meta($post->ID, 'forum_topic', true); if ($forum) : ?><a href="<?php echo $forum; ?>">Forum Topic</a>
And now if there’s a related forum topic, I make the custom field, add the link in that field for the post, and it shows up. No topic? No link!
Now if I can do that in reverse, that would be cool… related blog posts to this forum topic.