Ex:
I like using semicolons; they make me seem really smart.
Note that "I like using semicolons" and "they make me seem really smart" are two complete sentences already. To make them part of the same sentence, one need only add a semicolon. Adding words like 'for / and / nor / but / or / yet / so' change one of the independent clauses to a dependent clause, and the two can no longer be joined by a semicolon; you have to use a comma. Also, as you can see by my previous sentence, it is possible to combine the use of ", and" and the semicolon.