Today a persons personal information is typically held in numerous repositories internally within an organisation and externally. Therefore we may conclude that with the uptake of software as as service (SaaS), the number of instances of peoples personal data is likely to increase. More instances of personal data increase the possibility of privacy data being comprised.
Ordinarily this would be a logical conclusion. However, a benefit of implementing a Federated Authentication solution, is that privacy data can be maintained in a single repository.
The integration of individual applications (or services) in order to use a single repository/data store is achieved through open secure protocols. Further a complete set of personal data may not need to be proliferated across all applications, simple user role and user id may be sufficient.