A lot of times, we talk about the need for particular metrics, and how some metrics are worth a lot less than others. Usually, it's metrics like raw clicks, views, and likes that are deemed useless, while other metrics like conversion rate are the real important numbers. The reason for this comes down to pragmatism. If you're running a business, you're in it to make money. Getting 100 likes on a Facebook post doesn't earn you a single cent. Earning a single conversion does. Conversions allow you to figure out how well your marketing is doing, so you can balance