Use of the Semicolon

I am editing essays right now. I have one essay that has a semicolon in about every third sentence. Now, I have nothing against the semicolon. I think that it is a useful piece of punctuation and can be very effective when used properly. That being said, no one seems to know how to use it properly!!! It does not replace a comma. It does not replace a hyphen. It cannot be placed randomly in a sentence and still work. A semicolon joins two complete sentences together. That means that if there were no semicolon, the two sentences would still make sense as two separate sentences. What a semicolon does is create a link between the ideas in the two sentences. Here are some examples:

Marking essays is tedious; there are many errors that should have been fixed before the essays were handed in.

Few people really know how to use the semicolon; those that do understand its proper use look smarter than the average bear.

Heed my words and not only will people think that you are smart, but your essays will improve and the sanity of those marking your essays will be preserved.