IGN recently sold Gamespy to a company called Glu, and - presumably in the interest of improving their bottom line - Glu has started turning off support for certain games.
So far, Glu is targeting older games, such as Neverwinter Nights 1 & 2, Microsoft Flight Simulator X, Swat 4, Sniper Elite, Hidden and Dangerous 2, Wings of War, and Star Wars: Battlefront. For some of these games, it's still possible to host a server, and for players to join that server... as long as you know its IP address. For others, multiplayer has been effectively killed.
As you're no doubt aware, Battlefield 1942 uses Gamespy to find servers within the game. And the game is definitely old. How long will it take for Glu to drop support for BF42?
Luckily, Battlefield 1942 works just fine without Gamespy server support. Without Gamespy support, players will have to depend on third-party services like XFire and HLSW, as well as known server IP address lists on gamer web sites, to find servers. Some players have already given up on Gamespy because of its flakiness. Maybe it's time for everyone to stop using Gamespy completely.