It's great to have a way visitors can easily give feedback on typos etc. Also like the easy user interface to submit error's
Suggestions to extend the plugin.
IP tracking. Include the IP of the visitor
IP block function.
Add filed for suggested error correction.
Add field for name and e-mail, so you can interact with visitors how commit errors.
Option to only display error notification option to certain levels of WP users. This would be great for a editor team.
Didn't test if the error notification is sent to the post author or the general admin wp e-mail address. Would be great if this is the post author e-mail.
Thanks for writing this plugin.