Email queuing
 

What controls when the email queue is sent out?

• Is there a way to force it to happen earlier (I know individual messages can be sent immed., my question regards the entire queue).
  Does it happen in the middle of a user request, slowing down that user's page render, or is it down by some time of cron job?

unrelated: Is it possible to show the summary of the thread underneath the topic, instead of as a title= tag? Is it possible to shut off some of those boxes, such as the box listing permissions?


Related question: can I use the vbmail system to send multipart mail, with html and plaintext portions? I can set up the mail properly, just wanted to know if vb's system (which I would prefer to use) can accept multipart mimes, and how to set it up.