This article is taken with permission from Part 4 of the rec.games.mud FAQ, hosted at http://www.mudconnect.com/mudfaq/mudfaq-p4.html.

Contributor: Daniel A. Koepke (dkoepke@circlemud.org)
Server Family: DikuMud
Authors: Jeremy Elson, et al.
Language: C
Current version: 3.0 beta patch level 16
Status: Active development.
Primary Website: http://www.circlemud.org/
Primary FTP site: ftp://ftp.circlemud.org/

Technical Details:
Operating systems: UNIX, Linux, Windows 95/98/NT, Mac, VMS, Amiga, OS/2
Memory usage: Approxiamately 2MB stock w/ no players
Disk usage: Approxiamately 7MB stock w/ no players
Code size: 36000 lines of C code.
Derivatives: LexiMUD

History (summarized from the CircleMUD homepage):
CircleMUD began as an actual, running MUD administrated by Jeremy Elson on a system located at John Hopkins University. The name of the machine, a DECstation, was "circle" (i.e., its address was circle.cs.jhu.edu). CircleMUD was fairly popular during its run, but on August 26, 1992 Jeremy, increasing dismayed over the politicking involved in running a MUD, decided to shutdown the MUD and accept a coding position at JediMUD.

In May of 1993, Jeremy decided to dust off the CircleMUD source code and, after some work, release it. A summer's worth of coding produced CircleMUD 2.0 on July 16, 1993. There would be five more releases in the 2.x before the first release of 3.0 (bpl4) in September of 1994. Since then, Jeremy has built a small core of developers that do the official work on CircleMUD. The latest release of CircleMUD is bpl 16, which was released in September of 1999.

Features:
CircleMUD is intended to be a clean, stable base from which others can build their ideal MUDs off of. As such, it does not include many of the features that you'll find stock in Merc and Merc-derived MUDs. In essence, CircleMUD is a cleaner, more efficient, and more stable DikuMud. Current development efforts emphasize code and low-level feature maturity, rather than game mechanics, so a stock CircleMUD is nothing to get excited about.

CircleMUD is currently in a (sort of) feature-freeze while it is debugged. However, there is an active community of MUD administrators and coders that share their ideas and code with the rest of the CircleMUD community. Beginning coders should find the CircleMUD code to be very friendly.

Additional URLs:
Ceramic Mouse
CircleMUD Community Network
CircleMUD Mailing List Site