Keeps your CloudFlare DNS updated, creating records for all your new subdomains.
With mapped domains every new domain must be manually created on CloudFlare, as there is no way to do that through API at the moment.
We have asked if adding this feature was something they would consider, and they said : "It's under discussion, but not immediate."
If it will happen, we'll definetly work on it...
No it doesn't, you need the PRO version for that. CloudFlare WPMU Plugin – PRO