If you offer free membership registration on your site then it can be affected by spam signups (bots completing the registration form).
You can enable Google reCAPTCHA on your member’s registration form if your site gets a lot of spam signups. Google reCAPTCHA will cut down all the spam signup attempts on your membership registration page.
Enabling Google reCAPTCHA
Go to the Google reCAPCHA settings tab from the main eMember settings menu. Then fill in the API keys to enable this option.
Disable the ‘Anyone Can Register’ Option of WordPress
WordPress has an option that allows anyone to go to WordPress’s registration page and create a WP user account. This WordPress feature can open your site up for spam user registration. If you had previously enabled this option, you should disable it.
If you are getting a lot of spam WP user registration and you are not sure where it is coming from then this option is likely the cause for it.
You can find this settings option in the General WordPress settings menu of your site.
Settings -> General -> Membership

Our WP eMember plugin Does NOT need that option to be enabled.
So you should keep the “Anyone can register” checkbox unchecked.