After The Deadline is a project of Automattic (the creator of WordPress) which checks:
- styles (finds complex phrases, cliches, bias-language & suggests simple ones)
- and detects misused words (has a database of 1500 most misused words & suggestions)
Besides the artificial intelligence it already has, it is possible to add new rules & improve the application.
The project also has libraries for jQuery, Ruby & Python to make developing new plugins easier.