function my_category_filter($cats){
   //exclude these from displaying
   $exclude = array("Large Announcement", "Announcement", "News");
   $Catds = array();
   foreach ($cats as$cat){
      if (!in_array($cat,$exclude)){$Catsa[] = $cat;}
   }
   return $Catsa;
}

add_filter('the_category','my_category_filter');

function the_category_filter($thelist,$separator=' ') {
     // list the IDs of the categories to exclude
     $exclude = array(366);
     // create an empty array
     $exclude2 = array();

     // loop through the excluded IDs and get their actual names
     foreach($exclude as $c) {
          // store the names in the second array
          $exclude2[] = get_cat_name($c);
     }

     // get the list of categories for the current post
     $cats = explode($separator,$thelist);
     // create another empty array
     $newlist = array();

     foreach($cats as $cat) {
          // remove the tags from each category
          $catname = trim(strip_tags($cat));

          // check against the excluded categories
          if(!in_array($catname,$exclude2))

          // if not in that list, add to the new array
          $newlist[] = $cat;
     }
     // return the new, shortened list
     return implode($separator,$newlist);
}

// add the filter to 'the_category' tag
add_filter('the_category','the_category_filter', 10, 2);