Rah's Comment Form
Comment submitting with out comment preview, instead we use alternative spam protection: registration. Registration and login can be done with ign_password_protect and mem_self_register — with out these plugins, this plugin, rah_comment_form is “useless”, or it just doesn’t work. At least, in words of code, rah_comment_form requires ign_password_protect-plugin.
A cup of coffee