Email all users when a new content is published in Drupal 7
You can use the Rules module, a more powerful version of actions and triggers.
Configure a rule as follows:

React on event: (Node) After saving new content
Action: (System) Send mail to all users of a role

However, you cannot select the authenticated role here.  Instead, you will have to add another role to your site and use it instead.  (You can create another rule to automatically add that role upon registration.)
Also, note that the Rules module has this warning about sending too many mails:

WARNING: This may cause problems if there are too many users
of these roles on your site, as your server may not be able
to handle all the mail requests all at once.

So if you have a lot of users this probably isn't a good solution.