I'm trying to find information about how this app works in practice.

http://sites.force.com/appexchange/apex/listingDetail?listingId=a0N300000016ciJEAQ

We're on professional edition and the app information is unclear if it will work or not.  The App name implies that it won't work on professional edition, but the specs say otherwise.

I'm also a little skeptical that it's free.  It looks like a lot of development went into this product but why is it free and fully hosted on salesforce?  How does the publisher make money?