As promised my thoughts on leadership... if you would care to hear them.
Leadership Definition (read at your peril).
Disclaimer. Leadership is pretty complicated, and everyone has their own view of how it works or what it is. Ok, I can only give mine (Inspired by Voice of San Diego: New Reporter Guidelines thanks to Chemikazi for the source).
Leadership is part of the concept of reciprocity, where one party takens on the greater burden of responsibility in return is given authority by those who follow. So a leader has the ability to command as long as those who follow feel that their own concers and interests are aligned with the leader.
Ideally leaders cut throught situations where the group faces a prisoners and volunteers dillemma, these are occassions where rational self interest can burden a group instead of benefit it. Leaders are needed when coordination and discipline are needed to achieve goals that cannot be otherwise achieved individually.
As to how leaders achieve the goals thrust upon her by her followers depends on her tools and approach. Still there is a skill to being a leader, apart from understanding her role and responsibility, there are techniques that take practice and situations to she learns to see and react to appropriately.
Lets go to the Game Use.
Leadership is handling those who follow you. Leadership does not act like an Aura effect, its not something that works purely through the “projection” of a stature or a management perception. Its more of a mechanism for the maintenance of credibility and perservation of loyalty.
As said before, Leadership is not an aura effect. The leaders doesn't just posture and radiate some kind of infectious affliction that causes people to act irrationally contrary to their self interest (for that use some other skill). Because it is a mechanism of maintaining one's credibility and authority, it can only process a finite amount of individuals.
A leader, can maintain her credibility to a number of individuals equal to her leadership score. Normally, a person without a leadership skill can maintain IQ-5 or an average person can hold the confidence of 5 people at default. Default level of individuals, assume the character has not spent any point in the skill, are not chosen by the player but are those individuals who would most likely listen to this character. These typically be family and friends, and in odd situations not family and friends but only one's own professional colegues or peers. The GM gets to choose, and sometimes it may not be obvious to the player or the character who'se loyalty they begin the game with.
When a character spends cp, then she can command the loyalty (by making herself more credible) to inviduals she is choosing. This assumes the character tries to exercise her leadership among these people. With one cp, a character gains 4 people more loyal to her (from default of IQ-5 to IQ-1 at 1cp) . Every additional level means the character can work to maintain one other person.
Leadership is like building a rapport, there is some capital to be spent (time, effort, compassion, empathy, and sometimes material resouces) when cultivating an individual. A character is free to realocate who she cultivates. As a character gets better as a leader, she can cultivate more people at any one time.
A character with Leadership IQ+2 [8cp] can cultivate 6 people with the same amount of time an IQ-1  cultivates 4 people.
A character can choose to stop maintaining the loyaty of an individual. Where this relationship goes depends on circumstance. If the character wants to maintain this, then she will have to allocate some time and resources to maintain these.
The time the leader uses to maintain the loyalty of indivuals in game terms does not count in the time allocation. Consider the time used by the leader to cultivate her followers a “free” number of hours, this does not affect her task sheet. Of course. Ideally the leader is frequently exposed to these individuals, at least a few hours in a week.
Effects of Loyalty (or relationships).
To keep things simple, the GM can keep a loyalty score based on B518 loyalty of hirelings (which uses the reaction table in B560). Players can give their own Loyalty score to the GM as part of roleplaying and to hint at the party dynamics. The GM can impose, the way she imposes a player to role-play a situation, that the player role-play the effects of the other PC's leadership.
Every session the GM can ask the players how events of the session affect their Loyalty Score sheet (a list of the other players and how they feel about them).
Among Players, Loyalty and Leadership is very interesting thing to role-play and watch. Its where a lot of drama can be found and a lot of intersting decisions make for a very engaging story.
Among NPCs, Leadership is a handy tool to survive or to thrive in a situation by allowing the player to have sentient assets help her in overcoming the challenge. Of course these are not merely material assets to be discarded, these are sentient assets.
Leaders aren't always Awesome.
A character can be loyal to a leader out of respect (the most basic requirement). Other characters can admire, be enamored, trust, faith in the leader. Leaders aren't always necessarily awesome in the eyes of those who follow her commands.
Sacrificing Credibility or Political Capital.
Leaders who damage their credibility can incur a lasting penalty to their leadership score. Credibility is hard to recover, because once trust is broken it sets a precedent that cannot be easily ignored or overlooked.
Betreyals are very damaging to the character, despite how skilled she is as a leader. Such an act can make such huge investments of social/political capital worthless in a blink of an eye. The more a leader has invested in people, the more he or she stands to gain (or to lose) if this betreyal is discovered.
Other ways of getting people to do what you want them to do.
Battered Person Syndrome is basically commanding through fear. I'm not sure if I can recommend Intimidation to be used like Leadership, but instead of cultivating respect or credibility it cultivates fear. Although I don't see any problem of using it for such.
Note that now and then, in order to maintain the effect, let us call the leader as the "Tyrant", has to beat up the person or persons randomly to put them in a perpetual state of confusion and paranoia. Unlike leadership, there is a long drawn out contest of wills in this situation.
One cannot be a Tyrant and maintain her credibility as a leader without segregating the two spheres of people.
Other than fear, Lies and Confusion is a ways of creating and maintaining loyalty. I would imagine Fast Talk would be used for this tool. Again like Intimdation, the spheres cannot mix (if done so credibility is put to question). Similar to intimidation there is a long drawn out contest of wits, instead of wills, in this situation. If we were to follow the study of the book The wisdom of crowds for every other additional individual, (since skill just increases the amount of people to be tricked without increasing the amount of time to maintain status quo), there is a +1 bonus for everyone to their IQ roll to see through the deceptions/or the fudginess of the argument.
Some note the Game Definition and the Real World Definition.
Game definition can be twisted and has loop holes to begging to exploited. If taken as dogma, then it can be argued either way because it is after all an simple and imperfect definition created for the purposes of a pushing her