The gnome developers are hard at work making the first linux desktop, that do not look like a cheap windows/mac rip off, even better. There are stupid mistakes they made along the way, but still Gnome 3.0 gives the best experience free software can offer by default. Obviously there are more feature need to be included to make it a complete replacement for your good old Gnome 2.x. For the time being you can use these extensions to get some functionalities back.
Anyway, Gnome developers continue its work to have a consistent behaviour across the entire desktop. With its next incarnation, the team also escalates this behaviour towards individual applications. Meet Gnome contacts, the contacts application that you will see in the 3.2 version of your awesome desktop.
The application have a two window appearance. Left side for the list of contacts and the right side for the details of a particular contact.
The contacts will auto populate from the cloud services like your gmail through the web accounts (another feature planned for the 3.2). The contacts will be available to use on all the applications across the desktop.
The image shows how the contacts could be visible while composing a message in your evolution mail.