Matches in both items

matches.js

.filter('findMatches', [function() { 
  return function findMatches(arr1, arr2) {
    // We cache because JS has some funny properties.
    var len1, len2, i, j, matches, match;
    // Because you're passing in strings
    arr1 = arr1.split(' ');
    arr2 = arr2.split(' ');
    // Since the container will always be filled with matches
    matches = [];
   
    // Cache .length before loops.
    len1 = arr1.length;
    len2 = arr2.length;
    // Search
    for(i = 0; i < len1; i+=1) {
      match = arr1[i];
      for(j = 0; j < len2; j+=1) {
        // Add match to list, no soft checking.
        if(match === arr2[j]) { matches.push(match); }
      }
    }
    return matches;
  };
}]);

usage.html

<p>{{ title|findMatches:title2 }}</p>