In an interview to Barry Caudill, Senior Producer de Firaxis Games, we had the opportunity to know the main features of the multiplayer mode of Civilitazion IV. Here you have his answers about that important aspect of the game:

Could you fill us in on your plans for multiplayer in Civ IV? It’s always been one of the great holy grails of the series...

You bet!  This game was designed to be multiplayer from the ground up and we have been playing MP games for a year and a half already.  Players will be able to compete in traditional turn-based or simultaneous move games either on a network or via the Internet.  We will be using Gamespy for Internet matchmaking.  Other options include Hot Seat, Play by Email, and a persistent turn server we call Pitboss.

Coop will work in a similar fashion to what you would expect from an RTS like Age of Kings or Warcraft 3.  Players on the same team will share line of site, the benefits of wonders, research (they can even research the same thing to try to get it faster), unit trading, and share territory. All of these additions deliver a plethora of new strategic and tactical options to the players.

Do you think cooperative online play could work? For example, several individuals working together with different roles in the same civilization?

It has been tried in the form of what they call “Democracy games” at fan forums like Civ Fanatics and Apolyton.  That works in their format but it seems rather unwieldy and decidedly not fun for some of the people in a real-time multiplayer situation.  We are providing team play, however, and that should open up a lot of opportunities for creative players to specialize in various ways.  Players on the same team share line of sight, research, resources, etc. so the one closest to the line may concentrate on military while the one behind the lines can work on the infrastructure.