Currently, Salesforce and Google Contacts are the key differentiators.

At present, CardShark lets you push business cards directly to Salesforce and iPhone contacts, as well as Google Contacts (instantly via the FullContact web app). Additional integrations will follow - our goal is to allow users to transcribe business cards and push the contact info to wherever they want (from within one app, without cumbersome syncing).

We simply rolled Salesforce out first due to the fit and size of the market.