Envoy - Visitor registration that's changing how guests are greeted in companies around the world.
FullContact Card Reader - Automagically scan biz cards into LinkedIn/Gmail contacts
Proxyclick - Connect with Confidence
Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
TractionGuest - Safe, secure workplace for all.
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.