AS OF MAY 2016, THIS PLUGIN IS NOT BEING MAINTAINED AND WILL NOT RECEIVE ANY FUTURE UPDATES. 
CONTACT ME IF YOU’D LIKE TO LIST AN ALTERNATIVE HERE.
Shows word and sentence counts plus a readability analysis of the post 
currently being edited using three different readability measurements.
Readability analysis is an attempt to show how difficult a text is to read. 
There are several methods of doing readability analysis. The most popular 
methods are used here. The Flesch and Flesch-Kincaid methods use formulas based 
on the average number of words per sentence and the average number of syllables 
per word. The Gunning-Fog method uses a formula based on the average number of 
words per sentence and the percentage of “hard” words (words with 3 or more 
syllables) in the passage.
Both the Gunning-Fog and the Flesch-Kincaid give a score that is the number of 
years of education the reader must have completed to understand the text. 
Different types of writing calls for different scores. Technical subjects may 
require a higher level of education so a higher Fog or Kincaid score is 
acceptable. Informal writing may try for a score in the 7-10 range. The Flesch 
score is a percentage. The higher the value, the better the readability.

FD Word Statistics Plugin

Shows word and sentence counts plus a readability analysis of the post currently being edited using three different readability measurements.

CodeRichard

Configurator is a plugin that allows you to edit the <code>wp-config.php</code> file of your installation within the browser.
It lists every item in your <code>wp-config.php</code> file and displays it as a form so you can edit them as you wish. Just be wary though, making a mistake on crucial parts, such as your database user and password, can allow you to crash your WordPress installation.
If at any point your WordPress stops working after editing your <code>wp-config.php</code> through Configurator, fear not! Configurator makes sure to back up your <code>wp-config.php</code> file before overwriting it, so that in the event that anything happens, you can simple delete your <code>wp-config.php</code> file and then rename <code>wp-config.php.bak</code> to <code>wp-config.php</code>!
<h3>Compatibility</h3>
Configurator is tested to work from 3.0. I am not aware of any incompatibilities so far.
<h3>Disclaimer</h3>
This plugin is released under the <a href="https://tldrlegal.com/license/gnu-general-public-license-v2" rel="nofollow ugc">GPLv2 licence</a>. I do not accept any responsibility for any damages or losses, direct or indirect, that may arise from using the plugin or these instructions. This software is provided as is, with absolutely no warranty. Please refer to the full version of the GPL license for more information.

Configurator

Configurator is a plugin that allows you to edit wp-config.php in the browser.

FD Word Statistics Plugin vs Configurator