Cardhop - The Mac contacts app you'll want to use.
Peanut - Peanut is a Mobile Application for moms developed and published by Peanut App Ltd.
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.
CoFoundersLab - Meet 250,000+ entrepreneurs online
Contalist - The contact app for professionals and small businesses
PenPal World - Connect with people all over the world