“Even if I don't do anything with that data I think it's important to have that information... I started doing that when I did Create and Sell and launched it to the world at first, immediately I was segmenting but I wasn't doing anything with that data”

Segment at opt-in even if you do nothing with the data

Bake two segmentation questions into your opt-in from launch day — even before you're ready to act on them. It's brutally hard to retrofit identity data onto an existing 50K-subscriber list; far easier to ask each new subscriber on day one. The first job of the data is market research on your own audience; conditional emails come later.