I don’t like large numbers without context. Phrases like “they called for a $21 billion budget cut” or “the probe will travel 60 billion miles” or “a 150,000-ton ship ran aground” don’t mean very much to me on their own. Is that a large ship? Does 60 billion miles take you outside the Solar System? How much is $21 billion compared to the overall budget? (That last question is why I made my money chart.)
A friend of mine, Glen Chiacchieri, has created a Chrome extension to help solve this problem: Dictionary of Numbers. It searches the text in your browser for quantities it understands and inserts contextual statements in brackets. It might turn the phrase “315 million people” into “315 million people [≈ the population of the United States]“.