Data.com delivers leading business data inside Salesforce. Using the Data.com product suite, your sales and marketing teams have all the information they need to convert leads, close deals, and maintain customer relationships. If you want complete, accurate, and relevant customer information, then check out Data.com.
The Data.com product suite includes Data.com Prospector and Data.com Clean, with two levels of data availability and features for each (Corporate and Premium). Data.com also provides more offerings for Salesforce customers, including the Data.com Assessment App (available on the AppExchange) and Data.com Duplicate Management.
You can now purchase a Data.com Prospector license as an add-on to your Force.com license. Force.com does not work with the Salesforce Lead object, read Force.com help for more information.