Hi,
I was wondering if sending an individual email to several different lists at once would make a difference in the open rate vs. sending an individual email to just one list at a time.
Thank you.
It entirely depends on how your lists are created.
If you're buying lists? You'll get a crappy open rate.
If you're sending to a list of people who proactively opted in to your communications? You'll get a good result.
The number of recipients only really comes in to play for IP warming - if you have never sent email on that IP address before, then dropping a few thousand (20k+) emails at once will get you flagged as a probable spammer (because it's email activity that has never been seen on that IP address before). You would want to build up to that size of sending.
If you're already sending thousands of emails per day, you probably won't have a problem.
