How to send mass mail through vBulletin?
To send mass mail messages to your forum members navigate to your vBulletin admin control panel > Users > Send Email to Users.
Limit the number of messages that can be sent at once. If your account is hosted on a shared server, either contact your hosting provider’s support team and ask about the above limitations or check for it in the corresponding Terms of Service section.
Enter the corresponding information in the From, Subject and Message fields.
Then, based on different criteria you can filter the list of the recipients.
Click on Send located at the bottom of the page to send the mass mail.