Is there any module that can show whoever edits a node? Is there any module that can show whoever edits a node, just like how happens on Stack Exchange sites, where the user who edited a post is shown together the author of that post?
This article should be able to help you: Adding 'Last edited by name some time ago' information

I'm not sure how you want it to look exactly, but with a preprocess function and a simple template edit, you can add an editors information.  You can style this however you like and add/remove information, but to show the editor's name and the edit date/time do the following:

Add to template.php (or add the code to the preprocess_node function if already exists):

function neuco_preprocess_node(&amp;$variables) {
  $node = $variables['node'];
  $editor = user_load($variables['revision_uid']);
  $variables['edited'] = 'Edited by ' . theme('username', $editor) . ' on ' . format_date($node-&gt;changed, 'medium');
}


In your tpl file (node.tpl.php, node-YOURTYPE.tpl.php, etc):

&lt;?php print $edited; ?&gt;


Functions used: template_preprocess_node(), user_load(), format_date(), theme_username()