For a joke answer to be successful on Quora, it must meet the following requirements:
- It must answer the question as directly as possible, and show intent to inform the majority of readers and the original querent.
- It must be funny on some level.
- It must be a joke or parody answer, either obviously so to a large margin of answer voters; or subtly enough to escape their understanding, and lie in wait for a chosen few to snicker at now and then.
If one looks long and hard enough, it's not difficult to find a fair number of answers, even "best" answers, that could be considered "joke answers" – not merely humorous, mind you, but intentionally absurdist, mocking, or otherwise subverting the serious tone of the site overall.