Originally Posted by Dr. Drib
I echo Harry's comment and I'll add this:
It borders upon the obscene and the salacious.
1) It was going to rain today; therefore, the man carried his umbrella.
2) It was going to rain today, so the the man carried his umbrella.
3) It was going to rain today, so the man carried two items with him when he left his house: An umbrella with flashing, kaleidoscopic lights; and a lousy book by Kurt Vonnegut, Jr. that he eventually tossed into a rain-glutted gutter. I've always liked alliteration
, the man thought, as he danced a happy jig and watched the swirling waters swallow Vonnegut.
Here's how I was taught:
It was going to rain today; the man carried his umbrella.
Two contextually-related independent clauses, no splice needed other than the semicolon.