For those of you who use MailChimp you can now integrate incoming information into Heap CRM using WebHooks. To get your URL, go to your help tab and select integration:
For the particular list you want to integrate select "Settings:"
Then select "WebHooks:"
Paste your URL from Heap into this spot:
Now when someone signs up for this list that doesn't exist in Heap, they will be added. If they update their profile your entry in Heap will be updated (and they will be added to categories based on interest groups they select in MailChimp). If they unsubscribe they will be removed from categories based on their interest groups.