Reducing spam from open registration (add captcha) [OptimizeMember]
If you are experiencing a lot of junk signups when you have open registration on your OptimizePress/OptimizeMember website - you might consider adding a Captcha to your registration form.
We have a captcha system for our own forms which are created through OptimizeMember > Paypal Pro Forms > Free Registration forms - you can turn this on by going to OptimizeMember > General Options > Captcha Anti-Spam Security.
However for the standard Wordpress registration forms, we do not change anything with this core function so we would recommend a separate captcha plugin. There are several available in the WordPress.org plugin repository.