"The True Measure of Leadership is Influence – Nothing More, Nothing Less. True leadership cannot be awarded, appointed, or assigned. It comes only from influence, and that cannot be mandated. It must be earned."
I can see where this quote might convey leadership in that leadership comes from influence, but as stated in the comments, the Boss exerts influence, so does the Tyrant and the Dictator. I don't call that true leadership. Influence is the dynamic that is useful to the one attempting to lead. This is where the popularity and charisma "leadership" comes from, or should I simply say the effect those people have on others. There's too much power given to the one who influences that can be abused. Influence can be simply, either you do it or you're fired. That's a highly motivational influence, but the person making such demands is not a leader, it is one who only seeks self gain.
True leadership is not where the Leader gains benefit from the relationship, but the follower does. I simply use the phrase, "take care of your boys" when it comes to teaching leadership. As long as others are being taken care of they don't wander off. Parents take care of their children, the good teachers take care of their students, they have invested in the welfare of those following them. It has nothing to do with influence and persuasion to follow.
The charismatic leader that will champion the cause of their followers will be well liked. He's looking out for them, not himself and his vested interest is not in influence of his followers, but influence in answering the needs of the followers. Two totally different dynamics.
On the other hand, the quiet leader will be there, quietly in the back ground making sure each follower is successful in what they want and need to do. He/She offers up no directive influence, but is quick to support and assist.
Personalities of all kinds can be leaders as long as they take care of others. Ever wonder why the Scout Oath has the words "help other people at all times" in it? It is what defines leadership. Doing my duty to God and Country is not leadership, nor is following the Scout Law. Keeping myself physically fit, mentally awake and morally straight isn't either. But by helping other people at all times, means there will be many around who appreciate that help and will remain close for when the need arises again. People seek out those who can help them, they will seek out the real leaders, those who say yes I will help you.