Hi there!
Instead of standard notification on each new message, plugin will group messages by thread and send it every 15 minutess with cron job.
User will not receive notifications, if they are disabled in user settings.
User will not receive already read messages.
User will not receive notifications, if he was online last 10 minutes or he has tab with opened site
You can find email template with others BuddyPress emails templates:
yoursite.com/wp-admin/edit.php?post_type=bp-email
But its not too customizable at the moment.
