Date based items (and suggested changes)
Also, the Date-based sending sends an email at a specified time each day. My needs require evolving that to a single-send (basically a delayed send). However, a daily (duplicate) email has little value. In my limited testing, I set up a date-based email and it never sent out. I have to track down why.
One thing that I'm currently working on (and will hopefully share back) is rolling sends to facilitate an invite system. I have a single mailing and build up a large list of users in a queue. We want to roll the email out to registered users in chunks. To do that, we will find X number of users waiting the longest (sorted by timestamp, mentioned above), a flag to indicate they want the mailing, and a flag indicating they haven't been sent the mailing yet. After send, the flag indicating they received the email would prevent them from receiving duplicates.