How to Write Edit Notes
Whenever you make an edit on Musicbrainz, you will be asked to add an EditNote. This is usually just before you press the "Apply" button. Most edits need to be voted on by other MusicBrainz users, to catch errors and bad data. The edit notes are there to help the voters determine if an edit is correct.
If a voter disagrees they will usually add another edit note, describing the issue or asking for proof or clarification. If they don't, you can ask them in an edit note. Each edit note is sent by e-mail to everyone who did or voted on an edit. (This is why you should add your e-mail when making an account on MusicBrainz.)
There are two parts to this how-to: the first is for the edit notes you should add at the same time as making an edit, and the second is for adding further notes to discuss an edit, when necessary (i.e. when voting or answering a voter).
How to add edit notes when changing data
As described above, the primary reason for adding an edit note is to help voters to decide if the edit is correct. It is almost always optional to add an edit note, but you are strongly encouraged to add one for all but the most trivial and obvious edits. (There is another reason to add a note with "proof": in the future, someone may spot a possible error or need to check something; it's easier if they can look at the history of edits—like this one—and see the proofs.)
First in the edit note you should explain the edit, if necessary. Don't just add a note that says added new album or changed release date; this is immediately obvious to the voters. However, when deleting a release (for example) say if it's because it's a duplicate (and link to the pair) or if you don't think it really exists (and explain why) or if it doesn't belong in MusicBrainz for some reason. Try to think what you'd need if you tried to vote on such an edit for an edit on an artist or album you're not familiar with.
Second—and more importantly—add some kind of proof for the edit. Remember that most edits need to be voted on, and three unanimous Yes votes are needed to apply the edit immediately. This means that three different people need to check an edit; it is much more efficient if the original editor adds information to help them. Also, usually the editor is more familiar with the subject (because they have the CD, or they searched on the net in order to check their edit).
The best kind of proof to put in edit notes are links to where you found the information in the first place. If you find the information on the Internet, this means links to the web sites you use. If you add information from a CD you own, you should say this, but it's a very good idea to also search for the same kind of websites to give as proof. (Also, don't forget to add a discid when adding a new release you own on CD!)
- discographies: There are some sites with good (i.e. accurate) discographies; discogs is often a good choice for many kinds of music, and Encyclopaedia Metallum is a good site for metal. Often you may find a fan-site dedicated to a certain artist, for example 77ísland is a site dedicated to Björk's discography. Whether such sites have the artist's support or not, they are often detailed and quite accurate. You can find many such sites using a good search engine and searching for "ARTIST_NAME discography"; some deal with only original recordings, some try to exhaustively list bootlegs, compilations, and biographical info. Many popular artists have such links on their artist page in MusicBrainz, that's a good place to start.
- official sites: Naturally, you will often find such information on an artist's home-page or the record label's home page. These have the advantage of being official, but see below for a discussion of accuracy and trustworthiness. Also, not all artists have very detailed info on their sites;
- virtual music shops: Often shops like Amazon and the iTunes store can be used to find a record. These are generally good ways to prove that a release exists, but such sites are often inaccurate about detailed information, including track lists and release dates. Be wary that iTunes can only be accessed by users with the iTunes software, thus it's a bad kind of link.
- cover images: Often a good way to find/prove info about a record is to look at it's cover. Even if you use your CD's cover to do this, the voters usually don't have it. You can find scans of the cover on several specialized sites, like this one. If you don't find the cover then, you can scan yours and add it. For proof purposes, you can also just take a close-up photo with a digital camera (use "macro" mode), put it on any free hosting site and link to it in the edit note.
How to add edits notes when voting and answering
Anyone can add an edit note to an already entered edit. This includes already applied and not-yet-applied edits. Such notes are sent by mail to everyone that participated, including the original editor, voters that didn't abstain, and anyone else who added a note to that edit.
You can add an edit note to ask for clarification, for example if you don't understand the edit or you think something may be wrong. You should always add an edit if you vote No on an edit, explaining why you don't agree. Of course, when someone adds such an edit note on your edits you should answer with explanations and, if it's the case, proof.
Please try to be calm and courteous when discussing an edit, and try to be brief and (most importantly) as clear as possible. Always remember than it is very easy to seem harsh or impolite when using such messages. If you write a note (especially when contesting an edit) try to be very polite and friendly, and use smileys to soften the criticism. If you receive a negative note, don't become angry, and avoid arguing. Give proof, link to the guidelines you think support your position, and always be ready to accept your own mistakes. If you're not sure of something, you can always ask on the user's mailing list or on the forums. Many users are not native English speakers: be patient and understanding, write as clearly as you can. Apologize if you misunderstood something. And if by any chance you do encounter an asshole, that's no reason to participate in a flame-war.
Remember that all members are here trying to gather accurate data. MusicBrainz is many things to many people: some see it as a discographic catalogue, some as a file-tagging database. Be open to other points of view. It's not the end of the world if you need something a little different: you can always change file tags manually, for example. Also, remember what guidelines are: they were carefully chosen with many users in mind, so read them, understand and use them, but they're not the Word of God either. Sometimes there are exceptions, and users may need to make some decisions themselves. Use edit notes for this.
Another very important point is that the users that vote are often more experienced (i.e. were here for a long time), and that new users are often likely to make mistakes (e.g. not add proofs). A consequence is that voters often add very terse notes like "proof?" or "No, X is wrong", and new users tend to feel offended in such cases. Remember that the voters can't know if you are a very knowledgeable fan of the band, and they're not challenging you in person. Often they vote on large number of edits (remember, three votes are necessary for each edit), so they often don't have time for lots of explanations. Editors, try to understand what the problem is, read the relevant guidelines, ask for explanations (politely!) and the issue will be solved. Voters, try to be gentle, and link to this page if you spot a new user that isn't adding proof. Mistaken edits can be canceled (and reentered if necessary), or they may be applied and fixed afterward; it isn't necessary to cancel a whole "add album" edit only to fix a release date or some spelling.
No source is absolutely accurate. All may contain errors, including discographies, official sites, on-line shops and the album's cover. MusicBrainz strives toward an ideal standard of accuracy; it is not perhaps reachable, but we try to get as close as possible. This means that in some cases a single source is not enough as proof. It is recommended whenever there is any doubt about some information (the exact track list, the spelling of a song's title, the release date of an album) that you check several sources, and try to get as close as possible to accurate information. There is no single, simple set of rules to do this; this is why we need users to spot and fix errors, instead of just using a program to dump all the data it can find in the database. This also means that some people will reach different conclusions in unusual situations. Try to explain your reasoning, show your information ("proof"), listen to others, and try to reach a consensus. Even if that's impossible, don't start a flame war. It's not the end of the world.
Another thing: there is a partial consensus on MusicBrainz that incomplete data is better that wrong data. Rather than add detailed information "based on a hunch", without being able to find reasonable proof, add only what you can justify. It is usually possible to fill data fields partially. For instance, a release date has a year-month-day date and a release country; you can add only the year if you're not sure about the exact release date (Amazon is often wrong about these, for example), and use "unknown country" rather than "worldwide" unless you're quite sure about it (and can show several good sources!).