Amazon's all-time high isn't the ceiling. Cloud dominance and a booming ad business point to more upside ahead.Shares of Amazon (AMZN +1.62%) are hovering close to an all-time high of $254. But several growth catalysts can propel Amazon stock above its current price and potentially surpass its all-time high in the coming months.Improving demand visibilityAmazon's cloud computing platform, AWS, saw revenues grow 20.2$33 billion in the third quarter. The rapid increase in enterprise spendi ...