By this extension you can place a facebook comment box for each products separately in frontend
Demo : http://demos.soft-php.com/joocart-extensions/

Installation

1. Go to o your store admin panel. Navigate to Extensions -> Extension installer.
2. Click on the upload button. A dialog box should open.
3. Locate the installation file of this extension(facebook_comment_box.ocmod.zip) and select it.
4. Now this module named "Facebook Integration" should be visible in Extensions -> Modules.
    After locating it in the Module list just click the install button (“ + ” sign)
    Then edit this installed module and enable it.
5. Refresh the modifications from Extensions->Modifications
6. Go to System->Settings->Store Name[Edit]->Facebook Tab
7. Configure it by putting facebook application credentials and save
8. Now you will see facebook comment box in frontend product page.
9. Done.