Go servers have been around since the early-1990s. Many have come and gone, the best have survived.
The first and most long lasting Go Server is of course that know originally as IGS, the Internet go Server. This started in February 1992 at the University of New Mexico and moved around the USA before heading to Korea and its current home of Japan. It is currently owned by NKB Inc and promoted as Pandanet . It has had three official clients: gGo, glGo and Panda-IGS (originally known as the PandaEgg) and now recommends use of GoPanda. It has probably the largest multi-national usage and there are hundreds of players on it at any time. They also run a members' magazine and teaching service, and broadcast top tournament games live.
Various servers that worked similarly to IGS appeared around the world, but these have largely all now stopped or changed to java clients. They included NNGS (at one time hosted in the UK), LGS (Legend in Taiwan), Aurora or PIGS (Poland), CUGS (China University), CWS (Chinese Wiqi), HGS (Harmony in China) and WING (World-Wide Internet Gokaisho in Japan).
A large number of clients, as well as the official ones, have been written to work with IGS. Mostly they also worked with the similar servers. They were written to run under different environments (such as Windows, Mac, ST, Unix) and include: amigaigc, Black and White, Cgoban 1, Ergo, Go Assistant, Goban, Go Servant, Igc2000, Jago, jiango, MacGo, nextgo, oszigc, pcigc, qGo, STigc, TanGo, tgigc, TgWin, ViZiGo, WinIGC, xigc, Xgospel, zigc. Some clients also support the Go Modem Protocol.
KGS started life as the Kiseido Go Server in 2000, created for the publisher Kiseido. It had a more modern feel than IGS and has a reputation for being friendlier than IGS, mainly due to the use of rooms for different nationalities and so on. It can be run without a client or with the client Cgoban (version 2 or 3).
Multiple gaming sites have often featured Go. Yahoo! Games is one of the commonest. The Zone was also popular until Go was dropped from it by its later owner Microsoft on 19th June 2006 (they promise a new Messenger based service in the future). The most popular nowadays in Europe among Go players is PlayOK (formerly Kurnik - Polish for chickencoop). Another is Playray.
Play-by-turn or postal (email) servers are quite popular. Currently in use are Dragon Go Server (Sweden) and online-go. General game servers with Go are Little Golem (Slovakia), ItsYourTurn (USA), Richard's Play-By-eMail Server (gamerz.net), BrainKing, FICGS, JijBent (Netherlands) and qigame.com. Also KGS can be used by not setting time limits on a game and Sensei's Library hosts Rengo games. There is also an experimental site for "Four Color Go".
The ThaiBG server provides a server for Thailand, and others serve China, Korea and Japan as described below. Another server is BKGo. There was a European Go Server (EGS) set up in Croatia for championships but these were never held. The VietGo server from Vietnam seems to have gone as have the following: Instant Games/Java Open Go Server (JOGS) (USA), Planet, Mindsports, Jagex and Wireplay (UK), Cronix/Zagraj (Poland), Tabuleiro (Brazil), Interligence, Gamer, GIGS (Germany) and Newton Games (USA). Bright Lei's Game Land (Canada) seems to exist still but may not work.
Korean servers prove hard to us in the west due to use of Korean language, however some of the most heavily used servers are in Korea. Cyberoro (formed from Oro and CyberKiwon) is probably the top server, along with Dashn (Dash and Dot). Baduk World, Tygem and the Traditional Baduk Association also have servers, the last about life style as well as Go. Some corporate sites have games servers associated with them. Baduk TV (Onbadook), Neostone (netmarble) and NetBaduk (game.com) still have Go (Baduk) servers. Those that have gone seem to be WegoBaduk, Baduk King/Soodamcom, Play361, Gamenet, CyberBaduk, and MyBaduk (Koryo Baduk) from North Korea.
In China, Lshuzhi (playgogame.com), eweiqi.com, OurGame and Tom Go Server are still active. Harmony Go Server (HGS)/Weiqi online/China Tianyuan Network (CTN) now seems to be cngames.cn and China University Go Server (CUGS) and Chinese Weiqi Server (CWS) are now weiqi.net. QQ Weiqi is part of a general games site. Legend (LGS) is the biggest server in Taiwan. Those dead seem to be: China Road, Qifeng, QiGame, PlayGoGame, GlobalLink, HandTalk World, Haplink (HGS), TCL, Weiqi.com, Worldwide Go Web (WGS) and Shenzehen/Big Dual Match/China Games Center.
In Japan of course PandaNet (IGS) is the biggest server, but in 2004 the Nihon Kiin started its own "Taikyoku" server in conjunction with a Korean company. World-Wide Internet Gokaisho (WING) and World Web Go (WWGo) are also servers and the Nifty games server and the Bigglobe games server (Go Net) both feature Go. FGS is a server that has gone.
If you are interested in playing on the commonly used servers, then see our Play Go Online  page. For others, you will have to do a web search to find the current home pages or check the lists on Sensei's Library .