As a social media marketer, I believe that engagement should be the #1 focus-area, for many reasons. It shows early signs of growth and progress that you can assess and eventually add to your planning. For example, if your Twitter handle has a broad reach with low engagement, that's usually a negative, because it shows your content hasn't resonated well with your audience. Reaching millions of people means nothing if they aren't interested in what you offer. So now it's time to take action!