Following the closure of GameSpy last year, Civilization III, a 13-year old strategy game, now has SteamWorks multiplayer suppoort.
Publisher 2K Games has promised the transition to SteamWorks since April last year, but until now there were no instances of it happening. Now, with the aid of an update, the aged old strategy-game will have multiplayer integration through Steam. While the multiplayer will work the way you are expecting, you don't have the option of direct IP connection anymore. Save data won't be affected, but if you happen to use an old disc-based version of Civilization III, you'll need to contact 2K support for information on how to get sorted out.
Civilization III was launched in October 2001, and after 13-years, and despite the GameSpy's closure last year, Firaxis continues to support the game, bringing its multiplayer functionality to Steam.
Here's the developer's message:
The update that replaces GameSpy with Steam for multiplayer functionality is now available via Steam. The game functions identically to the previous GameSpy version with the exception that the "Direct IP" option has been removed as it is no longer supported. Save game data should not be negatively affected. If you own a physical disc version of Civilization III and are interested in receiving this multiplayer update, please submit a support request.
GameSpy's servers were shut down last year, and since then, a number of affected games - though not all - have transffered their multiplayer over to Steam.