Duiker101, connect with us at http://www.apptegic.com. We are working on this problem as well. Let's talk about how we could work on it together. There is plenty of room for differentiation from Mixpanel.
Apptegic, http://www.apptegic.com, has also been offering this for a while. We let mobile and web companies understand what each user is doing in their app on a per user and per account basis, and then respond directly to that user in Salesforce, by email, or real-time in-app.
On privacy, we designed in an inability to correlate user data across our customers. So, for example, we cannot know that an end user of Apptegic Customer A is also the same end user of Apptegic Customer B. With this in place, the data is used only for our customers to understand and better serve their customers.
My startup, Apptegic, www.apptegic.com is building a "user retention as a service" service. On a per-user basis, we can track events, patterns of events, and business usage (like # of photo batches sent). We can combine these to score engagement and we can segment and filter groups of users based on these combinations.
There are lots of other ways our Beta customers are using this info already. But many have asked for the ability to do targeted emails based on usage and engagement. We don't have email system integration into MailChimp, Constant Contact, and others like Paul described yet but we are working toward it.
Do you have suggestions on what a a minimal viable email system integration would be? Let people script a download of the list of emails that fit a criteria and script upload that into their mail system of choice?
If you have suggestions please comment below or contact me at kwirth at apptegic dot com.