Hermes downloads data from your social network accounts and uses it to enrich contacts on your mobile phone.
Hermes does not transmit any information from these services to any other service. Information is only retrieved and stored on your local device
The information retrieved is the same as you can view on your friends through facebook.com, twitter.com etc.
Your contacts' information is not uploaded to any system. All the matching is done on your device by pulling information from your social networks.