Envoy - Visitor registration that's changing how guests are greeted in companies around the world.
fruux - Free service that takes care of your contacts, calendars and more so you don't have to.
Proxyclick - Connect with Confidence
FullContact - Put the power of full contact information into your web or mobile apps.
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.