DiscoverOrg - DiscoverOrg is an IT sales intelligence platform providing technology marketers access to data, IT org charts, and real time projects.
Cardhop - The Mac contacts app you'll want to use.
Clearbit - Clearbit provides Business Intelligence APIs
The Contact Guru - Managing your contact list so you don't have to
Datanyze - The sales prospecting tool powered by technology data
Google Contacts - Google Contacts is Google's contact management tool that is available in its free email service Gmail, as a standalone service, and as a part of Google's business-oriented suite of web apps Google Apps.