Frequently Asked Questions about the CircleMUD License

I get questions about the CircleMUD license all the time. Usually, they are of the form: ``Hi, some friends of mine and I are doing X, is that violating the license?'' In an attempt to clear up some confusion, I've compiled a list of the questions I get most frequently, and their answers. Almost every question in this FAQ is a variant of a question I've actually received in email.

--Jeremy Elson

The License and its Enforcement

What is the CircleMUD license?
The CircleMUD License is the document which describes the rights and responsibilities you have when using the CircleMUD source code.

Do I have to follow the CircleMUD license?
If you're using code which is based on the CircleMUD source code, then yes, you do.

I started out using the CircleMUD code, but I've modified it pretty heavily since then. Do I still have to follow the license?
Yes, you do. If your code is based on the CircleMUD source code, you have to follow the license.

Wait, wait, you don't understand. I've modified the code really heavily and added all sorts of cool stuff. You wouldn't believe how different it looks now! Are you sure I have to follow the license?
What part of the previous answer did you not understand?

Oh, come on. Seriously now, do I really have to follow the license?
Well, what do you mean by ``have to''? Do you mean ``will I go to jail and die in poverty for failing to follow the license?'' No, you won't. To my knowledge, no legal action has ever been taken against anyone who violates the CircleMUD license. In fact, I don't even think the more popular licenses such as the GNU GPL have had legal action associated with their enforcement yet.

The threat of legal action shouldn't be what compels you to follow the license. The fact that it's the right thing to do should do so. Most people do follow the license for this reason; those who don't are generally considered persona non grata by the CircleMUD community. If you choose the less honorable path, don't expect the rest of us to be helpful, or for that matter friendly.

I know of someone who is violating the CircleMUD license. What should I do?
Contact the violators and point out their violations. Or, write to the CircleMUD Mailing List and let them know about your situation; you might receive some advice and encouragement. If you like, you can also drop a note to the CircleMUD core developers (but, read the next question first).

I am angry at the administrators of a CircleMUD because of something they did to me. They are violating the license. Can I contact you to report the violation out of spite, in the hope that you will make their lives miserable for me?
I get this question a lot. People who have been jilted, offended, or angered by MUD admins often try to use me as a way to get revenge. They report a license violation and expect to be able to sit back and get the last laugh while I start serving the violator with legal documents and get the MUD shut down. Sorry, but this won't happen. I don't have the time, money, or for that matter the desire to legally bully people into following the license.

What does the license say, and why?

What does the CircleMUD license require?
Not very much, really. You should read the full text of the license for the real answer to this question, but it basically boils down to: don't use CircleMUD to make money, and give authors credit for their work.

Is the license open to interpretation?
Of course: like a law, there are many gray areas and ``corner cases'' that are not covered by the license. The purpose of this document is to explore some of them.

Why didn't you use something else, like the BSD License?
I didn't have much choice, really. CircleMUD is based on DikuMUD, and therefore I was (and continue to be) bound to follow the DikuMUD license, which bans all commercial use of the server. The CircleMUD license is primarily inherited from the DikuMUD license, but with some clarifications on what ``commercial use'' means.

Fundamentally, I am not against commercial use of my software. The vast majority of software I write is under GPL, which does not restrict commercial applications per se. In fact, some of my software (tcpflow and emlog, at least) has been included in commercial products.

Why didn't you use the GNU GPL?
See the previous question. But, are you sure you'd want CircleMUD under the GPL? You'd be required to give away all your source code. I think that would be fantastic, but many MUD admins would cry bloody murder if they were forced to give away their ``secrets.'' So, in a sense, the CircleMUD license is less restrictive than the GPL: it allows you to keep your code a secret.

If you wrote a MUD from scratch today, what kind of license would it have?
Probably either BSD or GPL, depending on if I thought it was fair that admins be forced to share their code with other admins. In general, code sharing is a good thing, but I could be swayed by an argument that MUDs are constantly fighting for distinctiveness and should not be forced to relinquish it. (In this sense, MUDs are not like other software which almost universally benefits from sharing of additional features, bug fixes, etc.)

If I were writing a MUD from scratch (which I'm not), I would definitely not prohibit commercial use of the server. The Diku and CircleMUD licenses were written in a somewhat more innocent (and perhaps naive) time, when MUDs were almost all used by college students on their campus UNIX machines. In such a situation, the computing resources are free to the admins. Their time is, in essence, free. The CircleMUD license was an attempt to prevent what I viewed as an ``abuse'': some college kid taking the (free) code, running it on (free) resources, and raking in cash.

I think that old view of the world is now outdated. Running a MUD can be a major venture---it can require a lot of time, energy, and money. It's done by many people who do pay for resources. It's not unreasonable to expect someone to try to make a business of it, or to be compensated for their expenditures.

I want to follow the CircleMUD license. Am I allowed to...

(Most of these questions are taken, almost verbatim, from email I have received.)
...charge my players a fee for playing CircleMUD?
No, you can't charge a fee for playing the game.

...offer CircleMUD as a free service within an otherwise for-pay environment? For example, can I add CircleMUD to a for-pay BBS system?
This is sort of a gray area, but I think the answer is no, you can't.

...offer CircleMUD as part of a for-pay BBS system, if it's also possible for non-paying members to access it (although the rest of the BBS would not be accessible)
This is still skirting on a gray area. But, if it's possible for anyone to access the MUD without paying, then yes, this is okay.

...ask for monetary donations from my players?
Sorry, but no, you can't accept monetary donations.

...accept equipment donations from players or administrators?
This is sort of a gray area. If your MUD is really slow, and a player offers to send you a spare 128MB SIMM or extra Pentium motherboard he has lying around, I think that's okay. If you offer to make him an immortal in exchange for the SIMM, this is not okay.

I frequently get asked the question ``can a bunch of players get together and buy a new server for us?'' As I said above, I think it depends on factors such as special treatment that is given to the donators. If it's just a friendly group of folks who want to donate the server because they love the game, that's most likely fine. On the other hand, if the donation is motivated by (or causes) advancement or other special treatment in the game, you might be running afoul of the license.

...accept money in exchange for services rendered as a coder, administrator, area writer, etc., for CircleMUD?
Yes, this is allowed. Feel free to try to make your living as a for-hire CircleMUD coder.

...sell CircleMUD source code?
No, you can't sell CircleMUD source code.

...sell my modifications (patches) to CircleMUD?
This is another gray area for which I don't have a firm answer. On the one hand, you might see selling patches as essentially equivalent to selling your coding services, which (as I said earlier) is allowed. On the other hand, you aren't allowed to sell CircleMUD, so you might get around it by asking a potential buyer to download standard CircleMUD and then sell your patch-kit to it. Perhaps the only difference is the scale involved: selling to one buyer vs. selling to everyone.

...sell world files (e.g., room descriptions, mobile definitions) that I've written?
Yes, this is allowed.

...sell software that uses CircleMUD file formats (e.g., graphical world-builders, playerfile editors, etc.)
Yes, this is allowed. I'd definitely encourage you to make such programs open-source and free of charge, but you are under no obligation to do either.

...use CircleMUD header files in a 3rd-party program such as the one described in the previous question?
That's starting to fall under the category of ``using CircleMUD source code,'' but then again there aren't that many ways to say ``#define NORTH 0''. So, within reason, this is allowed.

...include CircleMUD source code as part of a large CD full of software, which I charge for?
I believe the DikuMUD license has language disallowing this, but my personal opinion is that it's not a big deal and should be allowed. CircleMUD was (and maybe still is) part of the Sunsite Linux archive, which has been sold on CD.

...give better stats, equipment, gold, or other perks to players in exchange for money, if I am an administrator?
No. Absolutely not.

...sell my CircleMUD character or equipment to another player, if I am a player?
Well, now we're certainly in a strange position, given the previous question and answer.

Players (not administrators) are allowed to sell characters or equipment, provided the following:

I struggled with this question for a long time. It's definitely a gray area, and potentially a slippery slope. On one hand, one could interpret this as violating the statement in the license ``you must not use CircleMUD to make money in any way or be otherwise compensated.'' On the other hand, when read in context, that statement really applies to administrators, and not players. The intent of that section of the license was to prevent an admin from extracting money from players in exchange for the right to play CircleMUD (see the question above, ``If you wrote a MUD from scratch today...''). The license never really considers the responsibilities that players have with respect to the license.

One might take a somewhat kinder interpretation of the license and consider the building up of a character to be a service rendered by one player to another. I like this latter view, despite being troubled by the potential loopholes that could be introduced by administrators giving special treatment to player characters which are later sold for money.

...advertise on my CircleMUD-related web site?
Yes, I think this is allowed.

...charge for services on my CircleMUD-related web site?
This is allowed as long as the services are not a prerequisite for playing the game.

...sell CircleMUD-related items such as t-shirts, mouse pads, etc.?
Yes, I think this is allowed, as long as you aren't giving any in-game preferential treatment to the buyers. We are starting to get into a gray area here, though.

...promote the sale of merchandise on my MUD?
I think this is essentially equivalent to the previous question; yes, it is allowed.

...set up a stock CircleMUD, making no changes other than the name, and then sell t-shirts from its website with just the name of the MUD, and the telnet and/or website address?
I think this is allowed; see above.

...create a mobile and an area, and sell, on the MUD's website, the t-shirts with a picture of the mobile and all the MUD's details?
This is okay, too, with the same reasoning as above.

...create an original world and theme for a world, starting with CircleMUD code, and later recode (from scratch) the codebase, identical in look and feel to the original CircleMUD derivative, but with none of the original Circle or DIKU code, and then make the MUD pay-to-play?
If there really is no code at all from the original CircleMUD, I would say it's probably okay. Sounds like a vaguely gray area, though.


Jeremy Elson
Last Updated: 21 August 2001