Sending mass emails (newsletters) in the background
Similar to how cPanel does EasyApache, you shouldn't need your browser open to continue to send a newsletter. When you have thousands of clients, it can take several hours to send out a newsletter.
It would be best if you could send it out, close your browser and it continue to do it in the background.
I can't count how many times I've accidently closed out my browser window and it cancelled the newsletter.