It's late, I'm tired, and I felt a sudden urge to type something without being mentally coherent. So I'm going to pontificate for a bit, and probably piss half of you off. But whatever, I'm eating cheese, so there.
First off, if you're not American, you probably don't know jack shit about this, other than what you skimmed on wikipedia this week. Second, if you're American, you still probably don't know jack shit about this, because it only comes up once every 4 years and you can't be bothered to remember it.
The Constitution of the United States of America, located here for your convenience. Most people have never read this. Like, legitimately read it from start to finish.
The Constitution is a thing of beauty. It was, and still is, one of the greatest documents in the world. I'm being serious. When you actually understand this, I mean actually understand this, nothing else can really compare to it. It's amazing.
Since we're on the topic of the Electoral College, that's under Article 2. Article 1 is about the legislature (Congress), Article 2 is about the executive (President), and Article 3 is about the judiciary (Supreme Court). Article 4 is the States, and 5 through 7 fill in some details. These articles are arranged by importance, and generally act as a ladder of power - 1 being the most important, 2 being slightly less, and so on (this has changed a bit over the centuries and various amendments). So from how it's arranged, you can see that Congress is designed to be the most important, and is the ultimate power. The first 3 compose the Federal Government, and since they come before the States, you can see that the Fed's trump the States.
(Not to confuse matters, but this is the original Constitution, and was the base framework for everything. There was a disagreement during the drafting, which I won't get into, but ultimately the Bill of Rights was immediately passed after the Constitution took effect. The Bill of Rights is the first 10 Amendments. So in other words, they created the Constitution, signed it into effect, then used the power of the Constitution to change it 10 times. Also various other Amendments were passed through history. End of tangent).
But yes, back to the Electoral College. What's all that about? To summarize a whole lotta history, the Founding Fathers realized something very important: power corrupts. So they specifically designed the worst possible government in existence. The most inefficient. The most uneconomical. The most fucked up thing they could imagine. Aka, democracy 
Ok, I'm exaggerating (but only a little). But the end result is, they took a look at the "government", figured out what was needed, and then cut it into many, many chunks. This is known as the "checks and balances" in the government. Another way of thinking about it is, they split the government into multiple little factions, then designed them to continuously fight each other. It's a machine that's poorly designed, and keeps smacking itself in the face with a frying pan.
By having the government fight itself all the time and squabble over power, it prevents any one person or group from seizing too much power. Because it someone gains too much power, the other parts of the government furiously attack it and seize power back. No one part of government can get too powerful without becoming a threat to other parts of the government, which then take action to protect themselves. And of course, try to boost their power, which triggers the cycle over again.
Massive inefficiency. But a surprisingly stable government.
Now imagine, loosely speaking, the following power blocks: Congress, President, States, The People.
In the modern system, The People vote for Congress and the President. But that's not the original system. Because, remember, the Founding Fathers didn't want anyone to have too much power. And that includes YOU. The people. They actually feared the people as much as a king. So they created the Electoral College.
You vote for Congress. You vote for your State legislatures. The States appoint Electors (usually done by citizens of a state voting in some manner). The Electors vote on who becomes President. The voting results are sent to Congress, which then determines a winner. Massively convoluted, right? It's designed like that.
Originally, in order for someone to become President, they needed to be approved by each of the following: Congress, Electors, The People. (The States are also indirectly involved, as they can change the rules regarding the Electors and can control them).
But why involve the Electors at all? Because the Founding Fathers didn't trust the people, and they didn't trust government(s). So they split the election up into several chunks and spread it out. In order to elect a President, you need multiple, separate, and distinct groups working together to agree. (Spoiler alert: It was also designed so that this process would - spectacularly - fail most of the time. If this happens, the decision gets thrown to Congress. BUT WAIT! Each State only gets 1 vote in Congress, and each State's vote needs to be collectively determined by that State's representatives in the House).
This got long and I'm tired, so I think I'll summarize the rest. End result being, the Electoral College was created in an effort to prevent the President from being "appointed", by requiring the President to survive votes from multiple groups across the nation. In addition, the Electoral College prevented a majority in any group from overriding the rest of the groups, and was specifically designed so each State had "relatively" equal power in choosing a President. In effect, a farmer from Buttfuck, Nowhere would have roughly equivalent voting power as Warren Buffet. And someone from South Dakota would have roughly the same voting power as someone from Maryland. Etc etc.
However, time has changed this (probably because we don't teach this anymore and it's confusing) (also probably because it's now easier to ramrod a candidate into the Presidency if they have enough money). Most things are decided by popular vote now, for one reason or another, but the fragments of the Electoral College still exist. And the point of the Electoral College, even in it's weakened, toothless state these days, is to spread the vote across the nation. To prevent a certain concentration of the population from overriding other parts of the population. Or in other words, to prevent the people of NYC from rolling over every citizen of Nebraska, Montana, Idaho, and Iowa combined.
So yeah. The Electoral College. It's here to stay.
Because changing it would trigger a Constitutional Convention, which is a whole separate can of worms I'm not getting into tonight.
If you made it through this post, this is probably you. If so, I'd recommend doing this.
