Friends Only

This eliminates the need to register for an username or password.

This plugin also blocks access to feeds.

At first load, the user is prompted to enter his email address to view the blog's content.

Installation:

Unpack and upload it to the /wp-content/plugins/ directory.
Activate the plugin through the 'Plugins' menu in WordPress.

What is new in this release:

• Redesigned session authentication system.

What is new in version 0.5.2:

• Fixed bug that requires users to log in twice in some WordPress configurations.

What is new in version 0.5.1:

• Allow users who are viewing posts through an RSS reader or email to view media.
• Disabled notification for failed login attempts when the form is blank.
• Small performance tweaks.
• Updated documentation.

What is new in version 0.4.4:

• Added wp_head() function so that things like privacy settings are honored.

What is new in version 0.3.4:

• Opened up access to XML-RPC to support the WordPress mobile client application (and any other apps that use XML-RPC).

What is new in version 0.3.3:

• Added support for the use of HTML entities in messages.

Requirements:

• WordPress 3 or higher

Limitations:

• It's not particularly secure, but it's a good tool for limiting access to only a few people.