Raven’s antispam – powerful and invisible fighter against comment spam. No set-up necessary, install and forget.
Details
Visitors with enabled JavaScript (99%+) see nothing – no annoying questions, no captcha, nothing. (Users with disabled JS see an additional text-field and a word that must be rewritten into the textfield.)
Note: this plugin is not able to check your trackbacks – to handle trackback spam, it’s necessary to use some other solution. (I recommend to disable trackbacks globally, since they rarely bring any benefit for your readers.) more….