FullContact My Contacts are those contacts that you have designated to Sync with FullContact. These are the connected sources that sync your contacts bi-directionally with connected Google, iCloud, and/or Exchange sources (depending on how they are set to sync). Your Contacts will be automatically updated by contacts from connected social network sources, or you can set those types of sources so they are added to My Contacts. Additionally, FullContact will offer Updates for contacts in My Contacts and will suggest possible duplicates.
You can edit Settings (or how contacts sync with My Contacts) if you go to your Settings page in any of our apps.