Depending on the service (social networks or e-mail services), Spread The Word Magento extension sends invitations in two ways:
A personal message
Facebook, Twitter, LinkedIn, Yammer, MailRu. All invitations and discounts come in customer's friends inbox's. Personal messages reach their recipients within 2-3 seconds. Facebook is an exception in terms of the way you can publish invitations and discounts. They are published on the wall publicly or privately depending on STW settings.
Gmail, Microsoft Outlook Online, Yahoo, address books in the LDIF and vCard formats and manual invitations.. All the emails to the invited friends get to the message stack where they are waiting to be sent. You can see the email queue in Magento Backend / Add In Mage:: / Spread The Word / Invitation Emails / Queue. These emails can be sent manually using the "Send now" button, or via Cron Job (automatically).
You can specify Cron Job settings in System / Configuration / Spread The Word / Cron Job Settings for Sending E-mails from the Invitation Stack tab. In this case you also need to have Cron Job set up on your hosting service.
To send your test e-mails, please go to Magento Backend / Add In Mage:: / Spread The Word / Invitation Emails / Queue and click "Send Now". In order to send emails automatically, please turn to hosting support service or website administrator to set up Cron Job. Ask them to set up Cron Job for running "magento_installation_root/cron.php" file every 5 minutes.