I am the technical product manager at Janrain.
The information others have provided is mostly right, but thought I'd chime in for clarity.
The Janrain Engage product does not store any of the user profile data we pass through to you. Some of our customers store it and some don't.
It depends on your needs. e.g. what profile based changes like experience customization you want to provide.
Some customers who don't want to store the information themselves use our Janrain Capture product to do so. They own and control the data. We just store all of the profile data in the repository we host for them.
Best,
Kevin Ernest Long
Technical Product Manager
Janrain