You can answer any question asked of you with 100% factual accuracy.
You can answer any question anybody asks you with 100% factual accuracy, even if you did not previously have the knowledge to answer the question.
You do not need to have had the knowledge previously to answer the question. However, the facts of the answer have to exist or have existed out in the world. For instance someone can ask you "What exactly am I thinking at this moment?", and the power doesn't work. But if that same person asks you "What did I write on page 5 of my journal?" you'd be able to tell them exactly what was written.
The answer will always be 100% factually correct, even if that answer goes against established knowledge.
The power will not work if you ask yourself the question, or if you ask someone to ask you the question. It will only work if the question is voluntarily asked. You can prompt someone to ask you a question ("Ask me anything!") but it won't work if you try to guide the person to a question you want them to ask you ("I wonder how many times I've said the word f**k in my life.") You retain any knowledge you have gathered via this power.
Additionally, the power doesn't work if someone poses a hypothetical.
You can use it to solve mysteries, beat trivia contests, or just help someone find their keys. However, it cannot be used to read minds, predict the future, or have knowledge of something you couldn't have under those circumstances, such as "Which Religion is correct?".
Specifically, the power will not work for 'Jeopardy!' because those are statements where the answer is a question.