More than one question per thread is of course allowed, but let me here list some reasons why there should preferably only be one question per thread if that is not immediately clear:

• The meaning of voting becomes obscure. Should one upvote/downvote a question/answer if the subquestions/subanswers are not uniformly good/bad? How should one compare an answer that only answers subquestion 1 versus an answer that only answers subquestion 2? Etc.

• Often readers only read the title question, and ignore other subquestions hidden in the main text.

• If a question is not already in the title, it becomes hard to search for similar questions.

• The number of possible threads becomes unnecessarily large, especially if the subquestions are unrelated.

• Certain subquestions may already be duplicates of other posts, while others are not.

More than one question per thread is of course allowed, but let me here list some reasons why there should preferably only be one question per thread:

• The meaning of voting becomes unclear. Should one upvote/downvote a question/answer if the subquestions/subanswers are not uniformly good/bad? How should one compare an answer that only answers subquestion 1 versus an answer that only answers subquestion 2? Etc.

• The question becomes too broad. Potential answerers may only answer partially, or get discouraged before they get started.

• Often readers only read the title question, and ignore other subquestions hidden in the main text.

• If a question is not already in the title, it becomes harder to search for similar questions.

• The combinatorical number of possible threads on the site becomes unnecessarily large, especially if the subquestions are unrelated.

• Certain subquestions may already be duplicates of other posts, while others are not.