A common issue many beginner WordPress users run into is blocking certain content from users that aren’t registered or logged in. Here is a short, simple solution in the form of a shortcode. Any content between the code block will only be output if the user has registered and logged in to their account.

You can paste this code into your functions.php to gain access to the WordPress shortcode.

add_shortcode( 'premium', 'mcp_premium_content' );

function mcp_premium_content( $atts, $content = null ) {
 if ( is_user_logged_in() && !is_null( $content ) && !is_feed() ){
  return $content;
 } else {
  return '';
 }
}

And now the following can be put into any post, page, or widgetized area to filter who sees your content.

[premium]**Any Content Here Can Only Be Viewed
By Registering and Logging In Users**[/premium]

This can be further refined by filtering by user types, but in this basic example I only checked if they had an account and were logged in.