This article addresses the problem of robot user registrations on all WordPress versions including WP 3.3.1. I would be very interested to hear, what is the purpose of registering all these users, what is the goal? Did you notice that despite your best efforts to allow only human registrations, the ranks of your registered users keep growing? All these are dead records in your database. Each new user registration is one record in “wp_users” table and about 15 new records in “wp_usermeta” table. And none of them ever change their default password. Total waste. You might even install a CAPTCHA plug-in to torture real human users with typing a four-digit code to…