Introduce a privacy statement.

readme.md

@@ -42,6 +42,12 @@ This plugin allows you to quickly swap between user accounts in WordPress at the
 
 See the [FAQ](https://wordpress.org/plugins/user-switching/faq/) for information about the *Switch Off* feature.
 
+### Privacy Statement ###
+
+User Switching makes use of browser cookies in order to allow users to switch to another account. Its cookies operate using the same mechanism as the authentication cookies in WordPress core, therefore they contain the user's `user_login` field in plain text which should be treated as potentially personally identifiable information. The name of the cookies are `wordpress_user_sw_{hash}`, `wordpress_user_sw_secure_{hash}`, and `wordpress_user_sw_olduser_{hash}`, where `{hash}` is an identifier unique to the installation of WordPress.
+
+User Switching does not send data to any third party, nor does it include any third party resources, nor will it ever do so.
+
 ## Screenshots ##
 
 1. ![The *Switch To* link on the Users screen](https://raw.github.com/johnbillion/user-switching/master/assets-wp-repo/screenshot-1.png)