How to hide the "Add comment" link in the teaser?
You can accomplish this with a custom module, as I found here https://drupal.org/node/1257788

Here is the code you'll need:

function MODULE_node_view_alter(&amp;$build) {
  if ($build['#view_mode'] == 'teaser') {
    // remove "add comment" link from node teaser mode display
    unset($build['links']['comment']['#links']['comment-add']);
    // and if logged out this will cause another list item to appear, so let's get rid of that
    unset($build['links']['comment']['#links']['comment_forbidden']);
  }
}