Theia comes with a proprietary email sending mechanism. It's not advanced, or flashy, but what it is designed to do, it does well.
Basically, the philosophy behind the MailQ system is pretty simple:
Sometimes web servers send emails slowly, and sometimes home servers have to rely on ISP mail servers; either of these, added to the presence of a large member database with notifications, will mean your site sending email can cause a dramatic performance hit.
That's where the MailQ comes in.
Instead of trying to send every mail there on the spot as they are triggered, what happens instead is that all pending emails are added to the database, with a respective priority.
The priority is an integer from 0 to 9; where 0 is a low priority and 9 is a high priority. The priority determines which emails will get sent first, where a pending email with a priority of 0 will get sent after all other emails with higher priorities have been sent.
Also, a priority of 9 means that the email will always be sent IMMEDIATELY, and hence: would function as if emails didn't need to wait on a queue before being sent.
Different types of emails that get sent from your site have different priority settings. To manage the priorities of emails that your site can send, load up the "tools" page, and navigate to the "email management" group of tools, and click "mailQ settings & priorities" (admin tool 057).
It makes sense to prioritize certain emails over others.
For example, welcome messages and activation codes are things that you want to make sure are sent out from your site as quickly as possible (if you're concerned with not frustrating your audience, that is).
Things like new poll notifications or new quiz notifications may be less vital to you and your site, and can stand to be sent later after more important messages have been sent.
How many emails should mailQ send at a time?
Depending on the speed of your server, particularly the SMTP server, you may want to adjust how many emails on queue mailQ will send each time it operates and sends a batch of emails. This setting can be an integer from 0 (which means no emails will be sent!) to 999. For sites on shared hosting, you're probably best off with a setting of something like 200-300. This setting can also be controlled using the "mailq settings & priorities" tool (admin tool 057).
