Push notifications in PHP using Amazon SNS/SQS?

On my site I'd like to do push notifications of comments like Stackoverflow does. Amazon SNS/SQS seems to provide a framework to do this but I'm having difficulty finding any code/explanation on the web for anything beyond a "hello world" equivalent.

From reading the AWS SNS/SQS documentation it looks like I need the following:

logic:

1. post comment/answer to a new question
2. create topic (for first comment/answer only)
3. publish message
4. subscribe to topic

PHP on the page where comments are posted (http://mysite.com/postCommentOrAnswer.php):

$comment=$_POST['comment']; //posted comment
require_once 'application/third_party/AWSSDKforPHP/sdk.class.php';
$sns = new AmazonSNS();

$response = $sns->create_topic('SO-like-question-12374940'); //create topic

$response = $sns->publish(
  'arn:aws:sns:us-east-1:9876543210:SO-like-question-12374940',
  $comment
);  //publish comment

$response = $sns->subscribe(
  'arn:aws:sns:us-east-1:9876543210:SO-like-question-12374940',
  'https ',
  'https://mysite.com/notificationsReceiver'
); // Subscribe to notifications

PHP on the page where notifications are received (http://mysite.com/notificationsReceiver.php):

no idea, thoughts?

Obviously, this is not close to being a complete demonstration and probably has some incorrect function calls but I was wondering if someone might be able to help build upon this?