I guess ultimately it is a question what do you want EL&U to become
- site for real specialists and experts only
- site for both language and linguistics 'newbies' and specialist, professionals, too
I strongly disagree with Jeff's illustration of the low quality questions. Here are some reasons:
1. The top questions do not tell you much
If you compare the quality (usefullness) of top questions at stackoverflow with EL&U, I think you will not find much difference: top questions are intrinsically voted on for their interestingness and not technical quality. This together with the landslide effect (which serves as justification and reinforcement) will bring such questions to the top.
To summarize: objectively best questions will usually have relatively modest scores.
2. Frequent answers do not tell you much
Another issue is the issue of the most common questions - there are and there will be questions that repeat subjects, themes or actual questions word for word. This is rather unavoidable as long as there is no real penalty for not doing basic research.
Here I would like to take opportunity to praise moderators and others in the community for linking to similar questions and very diligently closing real offtopic answers.
3. The examples of 'bad' questions are flawed
Differences between slang words for breasts
Profanities are a part of a language with many linguistically interesting aspects. Learning and clarifying details on the use or the meaning of them is interesting not only to adolescents, but to any user of the language. Here, I presume, the actual objection is to the fact that these questions have such high score and not to the fact that they are asked.
Summary: If there is a consensus such questions could be discouraged by the faq (or forbidden). Until then it should let be.
Don't understand the joke: my milk's gone bad...
Jokes, as a rule, employ very complex literary devices (or rhetorical figures). The whole concept of humor is very closely tied to linguistics and language, as anyone who attempted to translate more than one joke knows very well. I strongly disagree with closing such questions.
Faq says: 'Explain this joke...' is off-topic, unless it employs some subtlety of English language, but I think it is not unreasonable to claim that most jokes employ it and that even cultural references should be explained if asked as they tie into how the joke 'works' (how the literary or rhetorical device becomes really effective).
What is a more common expression in English for "move your bowels"?
Again we have the same problem as with example number one - the question itself is no worse or better than, for example: 'What is a more common expression for "move your car"?', however the two will never get the same score, because one is objectively much more interesting since it looks at language usage in the context of taboos, which by default has potential to be much, much more important as the subject is much more sensitive.