Alexa does not know – to anyone today, after an early, invitation-only beta launched in December.
Users want to be able to filter questions by categories like "most frequently asked questions," "newest questions," or general topic areas, like science or geography, and then submit the answer (assuming they know it). Amazon is looking to gamify the system. Users will earn points when Alexa uses their answer, and they can compete on leaderboards. You'll be able to track how often Alexa uses your question.
The main concern is fact-checking. Amazon does not seem to have any formality. Alexa users wants to get the answers as a thumbs-up or thumbs-down when provided with the user-submitted response, along with an Amazon-style star-based rating system that exists on the Alexa Answers website, but it's totally reliant on customers rating on their own.
Additionally, Amazon says that "Alexa may rotate between answers until she which seems like a poor substitute for an actual determinant;
Still, the way to make them smarter, and to get their customers to volunteer, is to take a close look at them to customers' recordings) is not the worst way to accomplish that task.