It's as important to understand what metrics not to track as those you should, writes Jon Miller. Avoid "vanity" metrics such as Facebook "likes" that only sound impressive. Focus on lead quality, not lead quantity, and on results, not simply on the amount of marketing activity. "[T]he worst kinds of metrics to use are 'cost metrics' because they frame [m]arketing as cost center. If you only talk about cost and budgets, then no doubt others will associate your activities with cost," Miller writes.