I use the Socrates theme and WP Stealth Note doesn't appear on my blog

The problem is common among many WP themes. Here's the technical explanation:

In header.php file on line 151, the theme loads custom jQuery version ignoring that one shipped with WP and thus replaces the built-in library loaded by Wordpress. As a result our plugin cannot access jQuery functions it requests to load.

The theme has to call wp_enqueue_script ('jquery') instead of linking the library hardly. It actually has to use wp_enqueue_script for every script it loads and wp_enqueue_style for every style.

As WordPress is now shipped with a newer jQuery version, the developer has to ensure there are no compatibility problems.

The Socrates developers are in the process of making a major overhaul to their theme. Hopefully, this will get resolved soon. Feel free to forward this article to them, if you are using WP Stealth Note and Socrates. :-)

For now, please switch to another Wordpress theme like one of the default themes like Twenty Eleven or Twenty Twelve.