History:What Not To Link To
There are some websites that should not be linked to using relationships, or which should be done in a special way.
Links you should not add to artists are iTunes, Last.fm, allmusic.com, CDON.COM and CD Baby.
iTunes is proprietary, the iTunes Music Store links are only accessible to people using iTunes who live in a supported country. This excludes people not running a supported operating system, those who choose not to install iTunes and those who don't live in the few countries supported by the iTunes Music Store. These links are therefore hard for many people to verify as being correct, let alone use. These links also tend to be ugly and include session data which is undesirable.
It is pointless to link iTunes to artists or releases.
The only exception is when a release is an iTunes exclusive. As these are unavailable elsewhere, it makes sense to add this link.
Please add that link only in the format http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewAlbum?id=80505691 and also explain in the edit note and annotation that it is an iTunes exclusive (to prevent it being removed in the future). Hopefully we might get a relationship type for these particular releases.
Last.fm uses MusicBrainz's data, so linking artists or releases to Last.fm is recursive and unnecessary.
Secondly, Last.fm is not a discography site.
Last.fm is neither useful as proof in edit notes, a place to draw releases from to add to MusicBrainz nor to use as a legitimate site for information, because Last.fm's data is based on the people submitting their tags and MusicBrainz's own data. The data submitted by the label companies are simply some numbers and the permission to play their tracks. Proper official or fan-made discographies are much, much better places to use as sources of information.
Linking to groups is not a good idea either, because anyone can make a group, while not necessarily bothering to check if a group for that artist already exists, and then you end up with several redundant groups for the same artist. TODO HelpWanted
CDON.COM is a site which specialises in Scandinavia (and the EU), something sorely lacking from Amazon and Yahoo!
However, it is not very useful to link to for 2 reasons:
Firstly, the only way to link to something on their site is to use the URL that you get when you search for something, which is ugly and is liable to change over time.
Secondly, it always includes session data because of the way that CDON.COM works. On the portal site, the first thing you choose is your locale which all the other links thereafter is based on. For example, a link to a release made by a user in Sweden would be unbuyable to a user in the UK and they would have to go and change their locale and then navigate back to the the release making linking pointless.
All Music Guide deliberately obfuscate their URLs to prevent people using their content without permission, and as such any links will be 'hacks', and are liable to not work over time.
CD Baby is slightly different than the other sites in this list, as it is completely OK to add links from CD Baby to releases in MusicBrainz, but not to artists.
The reason for this is that CD Baby is album-centric, not artist-centric, and as such, doesn't really have any 'artist pages' to link an artist to*.
Please link releases with "music can be purchased for mail-order at" to http://www.cdbaby.com/cd/somename where somename is the name that CD Baby has for the release. Hopefully, we'll have a 'has a CD Baby page at' relationship type in a little while.
- Note however, that in some rare occasions, CD Baby has artist pages which are simple listings of the website and the releases they have for the artist. The name they use for the artist page can be a little tricky to find though. If you want to link an artist to CD Baby's list of albums, try to find an URL in the format http://www.cdbaby.com/all/somename and enter that.
Do not link artists to CD Baby's search URL for that artist as it, as a search result, may well include other artists' releases (compare it to, for example, linking Google searches to artists).
In general, you should probably only link releases to places where they can be bought, and only when it is a less common release or a rare artist which aren't normally found in the usual online shops or the release can only be acquired from a certain place. Linking artists such as Metallica, Queen or Pink Floyd to places like iTunes or other big shops is completely pointless.
Usually indie artists and the like will have a separate store or an artist page at an indie record label site. You should link to that, but pay attention, if the label's site does not give a good 'artist' type link, then it is probably better to just link each release, in general that is usually the case.
Please do not link releases or artists to top level domains where a lot of other artists' music can be bought (e.g. http://somedomain.com) as it is pointless. It's the same as saying 'you can buy this at, for example, Amazon.com', the user must still search for the release they want to buy.
Also, always use "music can be purchased for mail-order at" unless what you are buying are files you can download, to which there is usually track or release-specific links.