Steve Puddick

This plugin prevents unauthorized admin users from damaging or compromising your website.
A common technique for hackers is to exploit vulnerabilities in your plugins or theme and try to create an unauthorized admin user for themselves. Once they have admin access they can do whatever they want to your website. They can deface it, display inappropriate content, or carry out many other malicious acts.
Restricted User Activity adds an extra step to the process of allowing Admin users to perform actions on your website. It achieves this by explicitly specifying valid Admin user ids in the wp-config.php file. Even if a hacker was able to create an Admin user for themselves, they won’t be able to perform any actions since their user id would not be in the valid user list.
Note: This plugin requires some technical knowledge about how the WordPress wp-config.php file works and basic PHP coding. A single line of code needs to be added to the wp-config.php file.

Restricted User Activity

Provides stricter controls for admin user creation and activity

S Hetjens

This plug-in restricts access to blog and feed. All anonymous visitors will be forwarded to the login page of WordPress 
before accessing the blog content. If access is restricted, rss and atom feeds will be disabled, too.
The feed can be activated as a private feed for each user. Every user will have a unique feed url to access it. That 
url is based on the username and an md5 hash of the hashed password stored in database. This plug-in will modify all 
by wordpress inserted feed urls to the user specific ones. But be carefull. If you content is confidential you should 
not activate the feed. There is no way to check which services are reading (and maybe publishing) the feed’s content.

Hetjens Registered Only

This plug-in restricts the access to blog and feed. Visitors need to login before accessing the blog. It offers a private feed for every user.

Restricted User Activity vs Hetjens Registered Only