Kontacts

Kontacts - Information: http://osdev.mine.nu/kontacts/

Web frontend:
http://osdev.mine.nu/kontacts/php/

Release Log (stored in Google Docs):
http://docs.google.com/Doc?id=df4cm6sc_2cw5f6njz

UPDATE: a major update has been released (2.1.0). We have completely reworked the synchronization logic, which now makes it possible to use one username in several phones, also because of this the synchronization process became less error-prone and also the application now works on some phones where it did not work previously. For more information see release log.

This program extracts contact data from your phone address book, and sends it to a server. The server stores all the contact data, and changes history to all contacts, so you can restore all changes of your contacts.
If your contacts are lost or corrupted, you can restore them from the server.
Even if you remove contacts from your phone, and remove them from the server, they are not lost. You can still restore them, through the provided web frontend for contacts administration. There you can edit contact data, restore them from history or restore removed contacts.

TIP:
Contact updating and creating in the phone may not work. In that case, search the phone for the settings for this program. Then make sure, that the program can read and write contact data. If you are afraid of losing or corrupting contacts, allow the program to read but don't allow to write contact data. In that case, contacts will be sent to the server, but won't be updated in the phone.