Cardhop - The Mac contacts app you'll want to use.
Reminder - A better way to keep track of your reminders 📝
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.
Noto - Email yourself. Fast.
Keep In touch - Keep in touch with thousands of people
TurboVote - Making voting easy with text and email reminders