From the FAQ:
What kind of questions should I not ask here?
To prevent your question from being flagged and possibly removed, avoid asking subjective questions where …
- every answer is equally valid: “What’s your favorite __?”
This is exactly why the questions in question are not constructive, more often than not they generate extremely low quality answers. The first question, Good books on sales for non-sales people?, generated:
The other question, fortunately, was closed before it had the chance to generate such poor answers. Don't get me wrong, when I say poor I mean in a Stack Exchange context, the suggested books may be wonderful, but right now the Stack Exchange model and format has no way of vetting such answers. How do we now which answer (or very small set of answers) is the best? Why would anyone down vote someone's favourite book? Questions that ask for lists of stuff can not be evaluated, every answer is equal, and thus are considered not constructive all across the Stack Exchange network:
I realize this is a lot of rules, a lot of guidelines, a lot of thinking. But it’s simpler than it looks. As Aarobot said in his post: real questions have answers, not items or ideas or opinions.
And yet, those questions are indeed extremely popular. Popularity alone however is not really what we aim for, it's always nice when a useful question is popular, but a completely different story when it's just popular:
Popularity is a tough thing. I’m tempted to call it a curse, but what we try to do at Stack Exchange is make sure that questions and answers are popular for the right reasons — because they are amazing resources for learning from your peers. If you want to slip a few jokes in there with the learning, that’s fine, but when the question devolves into little more than entertainment, I hope you can understand why our community moderators are obliged to step in and protect the community from, well … itself.
Every Stack Exchange community can shape those generic guidelines (to a point) depending on the unique characteristics of the community's expertise, but there's little chance that questions that have failed repeatedly on several sites will work on another. You mention that such questions are welcome and well-received on Programmers (where I'm a moderator), but that's not a very accurate statement:
And if you sort the 208 open ones by votes, you'll see that most of the high voted [book] questions aren't really requests for lists of books / references, or are questions on canonical books on very specific topics. In fact, we consider book recommendation questions that aren't on specialized and specific topics off topic, and close them asap.
Questions that are asking for external resources / references / books, and worst, a list of, are not questions that have much chance of building up to an amazing resource, for quite a few reasons: External resources get outdated, links rot, people tend to just post their favourite without much explanation, and they are extremely easy questions to answer, which explains their popularity. Thus, not constructive.
If you insist on raising the question of not being able to choose the best answer, the most common solution is to turn the thread into community Wiki as the other sites do.
No, Community Wiki is not a "get out of jail, free" card:
Community wiki isn’t only abused for “fun” or “getting-to-know-you” stuff, though. Many sites propose using community wiki to allow content that is on-topic and useful, but can be considered borderline or questionable in other ways. Someone notes that a certain class of question has problems, and proposes using community wiki as a quick fix.
If a question is valuable enough that you believe it belongs on the site, chances are you don’t need it to be community wiki! We welcome all contributions which improve the quality of a site and advertise its greatness to the rest of the world. If you allow a certain class of questions, but only under the stipulation that no one can earn reputation from them, you’ve strongly discouraged these sorts of questions. People aren’t going to put in nearly as much effort to ask them.
Instead, strive for quality. If you’re unsure a certain question class belongs on the site, don’t tolerate the worst examples — demand that these questions be awesome. Questions shouldn’t be swept under the rug with community wiki; they should get the same respect and treatment as the rest of your Q&A. If those questions are something you are uncomfortable showing to visitors … they probably don’t belong on your site.
If the OnStartups community decides that reference requests are valuable for the site, there's no point in marking them Community Wiki. If not, then there's no point in hosting those questions all together, Community Wiki or not. The problem here is not that these questions generate cheap rep for the participants, but that they don't add to the overall quality of the site, and Community Wiki is only meant to lower the editing threshold and not as an excuse for poor questions.