I will also be curious to see this. It seems logical to think you'll be able to use this people data to segment in the future, I think it's a huge part of the value of this new feature.

Also, if you're interested in automating emails based on analytics you should checkout http://getvero.com (disclaimer: I'm a founder). We're working on a Mixpanel integration as I type so we should pick up right where Mixpanel leaves off :).