WordPress Spam Blocker blocks comment spam by using a combination of time-based hash (a.k.a. Time Based Tokens, TBT) and JavaScript (AJAX). When a comment is posted the plugin validates a hash based on time (and some other parameters). Comments posted via automated means will not have a hash or will have an expired hash and will be rejected. Unlike using a captcha, this does not place any burden on the commenter. Are you tired of logging into your wp admin to see it loaded with comment spam and have to delete it? This takes up plenty of time that you can save by using Wordpress Spam Blocker.

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