Send email to users, manually or on schedule (digest of newest posts). Users can send emails to each other. Export function included. STILL BETA!!!
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OK, there are some administrator outside which treat their services very strict. Mass mailing can always be misused for spamming. That's why you should ask your admin for current restrictions on mail sending. Pass their answers to me. And by the way, if you are starting a serious business than you should not put your website on a cheap mass web host without any personal support.
Scroll down in settings menu and you will find the different capabilities. You can assign them to different roles, hence to your users. I would advice you to use the plugin User Role Eitor.
Post it at the plugin page: Email Users 2
That is nice of you. Donation link: http://1manfactory.com/donate
I don't know. Maybe.