What are the main policies and guidelines for writing answers on Quora?

Quora aims for each question page to become the best possible resource for someone with the same question. To this end:

Answer policies

Answers should make the page more helpful for people who are interested in the question

• Add comments about questions or other answers to their respective comment sections, not as a new answer.
• Answers that challenge an important premise in the question are allowed, but they must also be helpful for people seeking to learn the answer to the question.
• Humorous answers must also be genuinely helpful, provide meaningful explanation, and must not appear to misinterpret the question's intent.
• Answers that include information copied from other sites should make this explicit by putting the copied content into blockquotes preceded by a clear attribution of the source.
• Use images only to make answers helpful. In particular, avoid sex-related or sexually provocative images that are not directly responsive to the question.
• Image- or video-only answers should be captioned and (where applicable) accompanied with an explanation of their relevance to the question.
• The gist of the answer should be able to be understood without having to leave Quora to access an external website. Answers that cannot be understood without navigating to an external site and appear to be doing so for promotional purposes may be considered spam.

Self-promotion is permitted only as part of a sincere, helpful and direct answer to the question

• Self-promotion in answers is permitted only in the context of a sincere, helpful, and direct response, otherwise it is considered to be spam.
• Answers promoting products or services must include a disclosure of any affiliations that might inform the answer's interpretation.
• Self-promotional links that do not form a part of a direct and helpful response to the question are not allowed.
• Affiliate links are not allowed.

Answers must comply with site policies

• Answers must not violate the Be Nice, Be Respectful policy, e.g. by containing personal attacks, disrespectful or insulting attacks on the question or other answers, or hate speech.
• Answers should be written in the same language as the one you're viewing, and should have correct spelling, punctuation, and grammar, and sentence capitalization.
• Answers that advocate certain harmful actions (currently: child abuse, pre-meditated murder including genocide, suicide) are not allowed.

Answers that do not comply with the above policies may be:

• Collapsed by user downvotes
• Collapsed by moderation
• Deleted when they strongly detract from the question page even in a collapsed state (e.g., clear spam or hate speech), or are potentially harmful to the site or its users.

Upvotes do not validate an answer that does not comply with policies - answers with many upvotes may be collapsed if the consensus among moderators is that they are not in accordance with the policies described above.

Answer guidelines

The following are guidelines that users are encouraged to follow when writing answers, so that they are more likely to contribute to making the question page a great resource:

Answers should be truthful and authentic

• Incorrect, outdated, or otherwise misleading answers are not helpful.
• Answers should cite sources for data, scientific findings, outside research, or other factual information verifiable by a third party.

Answers should provide explanation

• Good answers explain why they answer the question.
• The opinions expressed or advice given in an answer should be supported with reasoning for the reader's understanding.
• Contrarian and non-obvious answers are more useful when they acknowledge conventional wisdom before adding a new perspective.
• Answers that link to another site or contain embedded videos should provide a summary and an explanation of the content's relevance to the question.

Answers should add information to the question page

• Post informative and helpful answers, even if you wrote the question.
• Upvote existing answers instead of posting duplicates.
• Avoid inside jokes that make question pages less helpful and accessible.
• Send any personal messages for the question author as a private message.
• Add personal messages for other answer authors as comments on their answers, use the 'Thanks' function, or send a private message.

Answers should be well-formatted

• Clear and well-written answers are more likely to be read, understood, and upvoted.
• Use paragraphs and subheadings to break up large blocks of text. This improves readability.
• Use bold, italics, and underline sparingly for emphasis. Do not use block capitals.
• Use the numbered and bullet point list functions for all itemized lists.
• Use the blockquote function to indent quotes.
• Use numbers in square brackets (e.g., [1]) to denote footnotes.