Well, this could be an enhancement to the newsletter project I suppose, I hadn't thought of that. However, I think it becomes quite intricate when we're talking about managing bouncebacks, unsubscribes, sheduling, let alone tracking and statistics.
I have sent up to 4,000 from my site but that was a long time ago and the repercussions of clickthroughs and sending mail caused the most horrible time for me, the server / db / site, simply didn't like it at that time.
One way you could possibly get around it is to send as a bcc, so it's in theory sending one not personalised is much quicker to send. When you send something that is personalised, it parses through each user, applying the name and that takes resources, so if you don't mine sending a bcc, then that's probably going to make a big difference.
And also you better talk with your hosting provider that you want to do this. I tell my clients they are not to send mail in this fashion, as not only does it use resources (and DNN is greedy on them) but it's imperitive to me, that I don't get my mail blocked because people unknowingly send email and people aren't expecting it, and the IP or IP range gets black listed. That's a real horror story for hosting companies running mail servers.
Also, their infrastructure might not be setup to handle it, believe it or not, so talking with the hoster will get you far better results.
I have my own email marketing application, but it's really only good for lists up to 5,000 in my opinion. And I have a seperate server with our other email application which is SQL based and runs with it's own com object, to manage scheduling, but it's not for public use, as it's one I use when sending 20, 30, 100,000 email for clients, and is a managed application.
So, I ended up purchasing a product from xigla.com - it's not as refined, in my opinion, as mine, it looks better but lacks alot of the functionality, but it's .net, resides happily within a dnn site, and the dlls run in the same bin folder (I mentioned this in another thread when someone was talking about running non dnn apps in the same folder) and it cost me about $450US I think, and it can handle bounces for you too. It does have an unsubscribe function, which I felt was flawed because it allowed me to import users with spaces preceding the email name so the email address wasn't picked up when people tried to unsubscribe and that annoyed some people, which I can understand, because they couldn't even change their settings, however, I now put in the option to unsubscribe from my site and not get delivered mail, and that seems to work too.
These are just some of my thoughts on the matter, since I really believe email communication is a great way to keep in touch with users, and I have started and stopped and started again, getting regular communication and your users, if the news is good, do appreciate it.
My 2 cents worth and a different perspective on the matter.
Nina Meiers