Backlinks are those links linking back to the current page. In DokuWiki you can see a list of pages linking to the current document by clicking at the pagename at the top. If your wiki layout does not have pagename you can find backlinks by appending ?do=backlink to the page URL.
To speed up backlink searching the fulltext search index is used. This means some restrictions apply to the backlinks:
A page with no backlink is called an orphan. It means that, as there is no link to it, no one can see it. However, it still can be accessed if you type it's URL, or through the search engine, or even via the index feature. There is also plugins available for displaying orphan pages.
You can disable backlinks altogether via the configuration manager (see disableactions). In order to remove the link of the pagename you have to edit the main.php of your template and replace the following:
<div class="pagename"> [[<?php tpl_link(wl($ID,'do=backlink'),tpl_pagetitle($ID,true))?>]] </div>
with:
<div class="pagename"> [[<?php print tpl_pagetitle($ID,true)?>]] </div>