This MOS says, under Wikipedia:Manual of Style/Disambiguation pages#Individual entries:
Keep the description associated with a link to a minimum, just sufficient to allow the reader to find the correct link. In many cases, the title of the article alone will be sufficient and no additional description is necessary.
I consider this to be a pretty central tenet. An ideal disambiguation page allows the user to quickly find the topic they're seeking. As the text on the page increases, it becomes harder for the user to quickly read and navigate the page in order to find their sought topic. Therefore, disambiguation pages should not include text that does not help the user to find the topic they're seeking. I don't see why any of these three statements should be controversial.
I am definitely aware that opinions can differ on what text is "sufficient to allow the reader to find the correct link", and I know that my approach tends to be more minimalist than other editors. For example, if "Foo" is a term used in baseball, and a user goes to the Foo (disambiguation) page looking for the baseball usage, and the disambiguation page includes one entry that looks like "Foo (baseball)" and no other entry that appears to have anything to do with baseball, I think "Foo (baseball)" is sufficient for the user to figure out he wants that link. I know others disagree.
What's leading me to post this entry is a fundamental conflict that I seem to keep re-encountering, even though I can't see how the MOS supports it, and I don't think the MOS should support it. From my understanding, the position of some others is that every entry on a disambiguation page should include a complete definition of the term; e.g., instead of "Foo (baseball)", it would be "Foo (baseball), a baseball strategy in which the shortstop and pitcher waltz together briefly after each strike." To me, the directive that the description should be "just sufficient to allow the reader to find the correct link" seems quite incompatible with a directive that the description should include a complete definition of the linked topic; it seems like it would turn a disambiguation page from a navigational tool into a list of definitions that also includes links. It also seems like there'd be a lot more text for the user to wade through to find the link they want.
I was prompted to post this by a recent dispute at Ace (disambiguation), in which User:Bkonrad and I disagreed on many (many) entry descriptions. I've posted some representative examples below to show the kinds of descriptions that, to me, seem unnecessary and noncompliant with the MOS. (Please understand I do not mean this as a specific attack on Bkonrad; it was just easier to take a bunch of examples from this one page rather than collect or come up with a list of other examples.) Really, though, I think they all come down to the core issue of whether each entry should have a complete definition of the topic, and, secondarily, whether the MOS should be revised to clarify this point, since it's apparently not clear at the moment. I would very much appreciate community input on this matter.
(Note that for all of these examples, as far as I can tell, there were no other entries on the page likely to be confused with these. Obviously, if there are two similar entries, more description can be necessary in order to distinguish.)
|Full definition version||My preferred version||Comments|
|* Ace formation, also known as single set back, an American football formation||* Ace formation, an American football formation||If the user is looking up a topic under the name "X", why would it be helpful to tell them it's also known as "Y"? They’re not looking for the topic called Y. In this case, X redirects to Y, but the Y article makes it clear in the first sentence why X redirects there, as any redirect should.|
|* Ace, Texas, United States, an unincorporated community||* Ace, Texas, United States||I have a lot of trouble imagining how anyone has ever been helped by the "an unincorporated community" description, except maybe if you need to differentiate between another place with the same name in the same region that is not an unincorporate community. But assuming that's not the case, I feel it can be assumed that the reader can identify the community by the state it's in.|
|* ACE Basin, collective name for the estuaries of the Ashepoo, Combahee and Edisto Rivers in South Carolina, United States||* ACE Basin, a body of water along the United States' eastern coast||No reason to think the reader will need so much detail to identify this topic.|
|* Ace (Wild Cards), a class of characters in the Wild Cards science fiction universe||* Ace (Wild Cards)||If a user is looking for a topic that is inherently tied to a particular franchise, why would the user not be able to identify that topic simply by the name of the franchise?|
|* Flying ace, a military aviator credited with shooting down several enemy aircraft||* Flying ace, a successful military aviator|
|* ACES (nutritional supplement), antioxidant supplements containing vitamin A, vitamin C, vitamin E and selenium||* ACES (nutritional supplement)||Unnecessary for identification. It prompts me to wonder, if the disambiguator weren't in the title, would the disambiguator be considered an adequate description? (E.g., if this link were just titled "ACES", would "ACES, a nutritional supplement" be considered adequate?)|
|* Acetylcholine esterase, an enzyme that hydrolyzes the neurotransmitter acetylcholine||* Acetylcholine esterase, a protein||This description doesn't even make sense if you don't already know what acetylcholine is, and if you do, you don't need to be told what acetylcholine esterase is.|
|* ACE Limited, a Swiss insurance company operating in 53 countries and territories||* ACE Limited, an insurance company||The additional information is unhelpful and unnecessary. (I'm imagining that it was deemed necessary to define it as a Swiss company, and thus subsequently deemed necessary to also explain that it operates in many countries. It's the only insurance company on the page.)|
|* American Clean Energy and Security Act of 2009||* American Clean Energy and Security Act||Unhelpful and unnecessary.|
|* American Copy Editors Society, a professional not-for-profit association||* American Copy Editors Society||Description for the sake of description. Nobody is going to come to this page, looking for this topic, who knows that it's a professional not-for-profit association but doesn't know that it's for copy editors.|
|* Association for Comparative Economic Studies, a scholarly organization supporting the study of comparative economic systems||* Association for Comparative Economic Studies||More description for the sake of description. The description adds virtually no useful information that isn't already conveyed by the article title.|
|* Antarctic Climate and the Earth System, a science programme of the British Antarctic Survey||* Antarctic Climate and the Earth System, a climatology study||My preference was actually to use no description; the user seeking this will know they want the entry associated with the Antarctic, and there are no other uses on the page that look remotely similar. Adding "a climatology study" was my failed attempt at compromise.|
|* Ace Records (United Kingdom), founded in 1978, named as tribute to the U.S. label
* Ace Records (United States), founded in 1955 by Johnny Vincent in Jackson, Mississippi
|* Ace Records (United Kingdom), founded in 1978
* Ace Records (United States), founded in 1955