If you use the Synchronization Tool for syncing contacts between MS OutlookTM then your account will have "Private" Contacts that only the Account Logged in user can see. That may be fine for a single user environment, but if you have a Team - you may want to share your "Private" Contacts by making them "Public" Contacts.
NOTE: A "Public" Contact simply means other authorized users of your account can see the details of that record. It does not mean anyone can see the account - only authorized users in the account.
Search for all of the Private Contacts and pick those that you wish to make "Public".
Once the search nets all of the "Private" Contacts, then convert those you wish to "Public"
Select the contacts to convert after submitting the search
At the bottom of the selected contacts, pick "Update a Value"
Once a Contact has been made "Public" you may not make it Private again.