If this mod has been submitted or done I must apologize.
E-mailing clients and users in the form of newsletters has probably bitten 1or 2 of us. The forum Admin has users that are waiting for there newsletter and the admin has isp's breathing down there neck because AOL or some other host got 12 e-mails back to back from the forum.
I think there should be a mod that will divide the e-mail/newsletter into groups and send them out in increments, rather that sending out to 300 users back to back send 10 wait 3 minutes send 10 wait 3 minutes ................
Or the number of e-mails at whatever increment can be left at the discretion of the forum admin, to find what is safe for them. I just wish I knew enough coding to do this myself because I believe this would help a BUNCH of forum admins.
While a mod isn't yet available todo this the next version of SMF will have the option to choose how many e-mails are sent per batch.
For the moment you could try integrating your site with phplist (http://www.phplist.com) although this is not an ideal solution
Sounds great. Just because some systems think that it's spam, we are the ones suffering.