Successfactors

Dear Experts,

I have some very basic queries on SAP-Successfactors. Although SuccessFactors is the buzz word going around, I couldn’t able to find much information on this.

1.     What all modules SuccessFactors support and how they interact with SAP HCM or any application

2.     What is the implementation and data migration strategy?

3.     Is SAP HCM will fully transformed in to SuccessFactors in coming future?

Thanks in advance. 

Regards,
Swati.