A more private way to use WordPress without the hassle of passwords and such. Logged out users can only single posts, and only if they know the exact URL.

privacy-please.php

<?php
/*
Plugin Name: Privacy Please
Description: A more private way to use WordPress without the hassle of passwords and such.  Logged out users can only access single posts, and only if they know the exact URL.
Author: Evan Solomon
*/

/* Only allow singe page views */
function only_singular_requests_for_you() {
	if( ! is_user_logged_in() && ! is_singular() )
		wp_die( 'We can haz privacy' );
}
add_action( 'pre_get_posts', 'only_singular_requests_for_you' );

/* Don't let anyone guess URL's */
function no_redirects_for_you( $redirect_url) {
	if( is_user_logged_in() )
		return $redirect_url;
	wp_die( 'We can haz privacy' );
}
add_filter( 'redirect_canonical', 'no_redirects_for_you' );

/* Don't give away other URL's with adjacent post links */
function no_adjacent_posts_for_you( $format ) {
	if( is_user_logged_in() )
		return $format;

	return false;
}
add_filter( 'previous_post_link', 'no_adjacent_posts_for_you' );
add_filter( 'next_post_link', 'no_adjacent_posts_for_you' );