Private-Public Morpheus is a really useful plugin that allows you to create tiny pieces of code (content) within your posts that get replaced with one of two versions of Custom Fields. This plugin is like hitting the subscriber (leads) motherload. If your stuff is tempting enough people will subscribe.

The difference between this and other Subscribe To Gain Access scripts mavens use on their sites is that this one actually validates the email address. 90% of the Subscribe For Access boxes on mavens' sites give access regardless of the email address you enter. And that blows!

An example explains it perfectly

Text of your post:

Get the cool script here [pp:CoolScript].

Custom Fields

You need to create a public:CoolScript Custom Field to be shown to all non-registered users or in other places than the single post page. And the private:CoolScript Custom Field is shown on single post pages when user is logged in. As you see, I did not create these Custom Values (for CoolScript) and the above has remained unreplaced.

A Live Example

Look below.

You are not logged in. I don't know you stranger!

See how simple it actually is. The above paragraph changes based on your login state. Try it in two browsers, one logged in and one not. And it will show your name which demonstrates use of inline PHP snippets which is big if you know how to use them. This is the snippet I use within the private:replacement :

<?php global $current_user; get_currentuserinfo(); echo $current_user->display_name; ?>

The Public:* Can Be Shared

If there is no public:CoolScript the plugin will look into Settings - Reading - Public-Private default public value. This way you can set a general public version and distinct private: for each tag. As you see I have the same text everywhere I share code. This way I don't have to add a public: for each snippet I add. But I could create distinct publics for each post.

It's Pluggable

This plugin is also expandable by other plugins. It exposes filters that are all described in the documentation file attached as PDF. Make sure all internal HTML is escaped as <?php ... ?> code is actually handled as inline PHP. Make sure you have &lt;php ... ?&gt;. You can add live code and db queries to the replacement and actually add complex replacements inside your 'static' content.

This stuff is for developers only and not of much use to regular bloggers who just want new subscribers.

To Wrap It All Up

It's the same plugin I use here when sharing code. Make sure amateurs know how to subscribe to your blog. You can add a link in the public version of the text that explains how to subscribe to a blog with some screenshots and guidance.

It's easy to use this plugin and make it easy to subscribe for those who find it hard!

PS: By using the Inline PHP potential you could add the registration form right inside the public default block. I'll leave that to you as a test and I'll publish the solution in a few days.