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.

Transferslot - Easily buy and sell side-projects

Apple Contacts App - Access and edit your contacts from personal, business, and other accounts with the Contacts app.

MicroAcquire - A free & anonymous startup acquisition marketplace

Windows Contacts - Windows has many extraordinary organizers, and in the event that you include distributed storage, then you presumably have more.

BitsForDigits - An acquisition marketplace for profitable internet businesses. We make it anonymous & free for owners of $100K+ revenue startups to attract full & partial acquisition offers. Free for acquirers to join for a limited time. No commissions, ever.