WordPress sites administrators often encounter a problem - zombie or fake users register to your site using fake Emails. The emails they use often strictly follow the Email format so it's hard for our program to judge if they are valid or not. Although we can prevent these users from really using our sites by sending activation Email, still they are a waste of database space and make it harder to manage members. As a result, an Email whitelist is needed to filter these annoying registrations. Geek Mail Whitelist is a plugin which can allow users with certain emails to register to your WordPress site by adding whitelist rules. What's more, it supports regular expression rules which makes it more powerful to fit all kinds of situations. And it is COMPLETELY FREE! Github page: https://github.com/gongwan33/geek-mail-whitelist Description - Allow certain kinds of users to register to your WordPress site by adding mail whitelist rules. - Super simple to use