Our Salesforce Nerds developed a custom tool built on Force.com platform, where the tool scanned the entire Accounts and Contacts in their Org and identified the winning records and the corresponding duplicates based on a set criteria. After the manual verification, the tool merged these identified duplicate Accounts and Contacts.
Our Salesforce Nerds came up with a brilliant solution of having a layer of Password Authentication sitting over these public sites that enabled customers to login to the sites using their email/password combination but allowed them to view only the relevant data.
Salesforce Nerds within us designed a brilliant solution for our client where they were presented an Administration screen to enter the fields returned in the REST API call for any of the Salesforce Object and from any system