I have a site which is a tourism guide for beaches. I want related content to appear on the sidebar on single entries, such as how to get to the beach or travel stories, while the main section of the article appears on the main column.
The way I solved it is a bit intrincate, I use a custom tag on articles where I want the sidebar, which is checked by an if statement (get_post_meta) on sidebar.php. Then I use the get_a_post plugin (tweaked) to display the content of a separate post (marked private) with the slug name $post->post_name . "-sub". (check at http://www.almanaqueazul.com/?p=37)
This is an ugly hack, and too complicated for regular use.
There must be an easier way, right? I've thought maybe there is a plugin that hides text between quicktags in an entry but then allows me to display only that text, if present, with a separate template tag. Or maybe there is another way?