Let's say we send about 100k emails per day to our users. These are all transactional emails ("You received a new message",etc.)
In order to reduce the number of emails we group those transactions into summary emails and send those summary emails every 6 hours or so. So every 6 hours or so we send about 25k emails.
From particularly hotmail's perspective is it a bad practice to send all these emails every six hours.
Would it be better to send these emails every hour for instance?
Thanks, Haluk