Hello Forum... My name is Richard Buss and I run YNOT Mail. If you are looking for a system to use to send out bulk email, you should look into YNOT Mail. We use Interspire for our user interface, but that is only the front end. We have a very custom back end, and use DKIM and SPF, approved senders, etc. Check out YNOT Mail at https://www.ynotmail.com/ and contact me on Skype at rochardbuss with questions.