This plug-in is mostly of interest to Swedish, Norwegian, and Danish authors.
Lixtal calculates the readability index of your entry, the so-called "LIX-tal," which is a simple measure of the complexity of your text. As the Lixtal increases, the text will appear harder to read.
You can use to plugin to get an indication of how well your written communication corresponds to your target audience. Note that the metric makes sense only for the Scandinavian languages.
Perl - HTML::Parser
Perl - Encode