I thought about this after my first perusal onto the forums, and learned about the heartaches caused by the medal situation. Different ways of utilizing the alliance system built into Evony can easily be compared to governmental models used in real life.

Now, there are several dozen different governmental models, but most of them are only minor changes from one to another (ie: a theocracy and a dictatorship are very similar, except the rulers in a theocracy believe their power comes from their religion, instead of themselves), so we will focus on the three most common governments: Dictatorship/Tyranny, Monarchy/Empire, and Republic/Confederacy.

In a Dictatorship/Tyranny, the ruler(s) raise themselves into power. They do this by amounting great power and influence, either through great financial resources and/or underhanded 'dirty' tactics, and then use that power to rule the masses.
This is the person who plays Evony and uses his personal money (great financial resources) and/or 'dirty' tactics (medal farming) to amass great power and influence (many medals) to rule the masses (many cities).

In a Monarchy/Empire, power is amassed similarly to a Dictatorship, but in this case the ruler uses his/her power to subjugate lesser Lords/Ladies throughout the land in order to expand their influence upon a greater stretch of land than a Dictator by himself/herself could ever hope to. These lesser Lords/Ladies learn very quickly that they must do what the ruler says, or he/she will have to accept the consequences.
This is the person who uses the same tactics as the Dictator did, but he/she is not happy just to rule his/her own cities. This player creates an alliance, and forces others to join this alliance through threats.

In a Republic/Confederacy, power is only amassed through numbers. The common people band together, uniting around a single banner, and creating a whole that is far stronger than each member is individually. Working together is key in a Republic/Confederacy, as members are brought together by choice, not by force.
These are formed by players who do not have great financial resources (unwilling to spend their own money) and refuse to use 'dirty' tactics (medal farming), and as such they typically own fewer cities individually, but because there are so many players who fit into this category, these alliances can be just as strong.

Like I said, these are just thoughts I had one day, and thought I would share on here. What are your thoughts?