Windows 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.

FullContact's apps let you keep all your contacts in one place, automatically up-to-date. This social contact management software automatically cleans your contacts, enriches them with social profile data, and continually syncs them across devices with all your contact sources. You can also merge duplicate contacts, scan business cards, capture email signatures, and more.

A fully fledged, free email server solution, an open source project (GPL v2).

ID Book is a handy, easy to use application specially designed to offer users a simple address book.

Syncs contact between various third-party services and helps to clean them up and merge data.

E-Z Contact Book is a free easy to use yet powerful Windows program to store and manage contact information. You can use it as a business directory, customer database, or a personal contact address/phone book.

Address book program providing unified, flexible and simple interfaces for you to manage and lookup contact info of people and organizations.

KAddressBook stores all the personal details of your family, friends and other contacts.

Advanced Phonebook is a convenient alternative to a regular phone and address book. All necessary functions are available for storing contacts and working with phone numbers and addresses. Special features include alphabetical index, groups and categories, search and sort, and a variety of HTML and CSV report options. In addition to phone numbers, Advanced Phonebook can store all other contact data such as email addresses, Skype, AOL, MSN, etc.

Corporate Directory is an Active Directory phone book that reads contact details of everyone in your organizatin. It allows you to find any contact extremely fast!Corporate Directory is the fastest and most user friendly phone book software. It will automatically read all contact details from Microsoft Active Directory. Simply install on any computer and get instant contact details look up.No more chasing after contact detail updates. With Corporate Directory every employee can update his own contact details back to Microsoft Active Directory.Easily attach photos to get the personal touch. Using photos is the best way to let employees recognize each other and to make their communication more tangible and natural. »

CopyTrans Contacts makes it easy to manage iPhone contacts, calendars, notes and messages from the comfort of your PC. Key features include editing, backup, export, import and transfer of iPhone contacts, calendars and notes.

adx is a minimalistic but massively web enabled address book running completely in your browser. How it works: addressbook.XML + XSLT = HTML in your web browser. No server or any other addon/plugin. Just a pure browser application which can run local on your computer/device or on web server.