I've encountered the same grammar error three times today, so as a public service announcement I thought I'd do a little refresher session for my readers to be sure you won't inadvertently make the same mistake when you're out in the world.
Then vs. Than.....
"Then" is an adjective or adverb, and indicates time, sequence, or consequence. It can also be a noun, but that's not when most people misuse it.
"Than" is a conjunction that functions either as a comparative between two adjectives/adverbs or to indicate preference. It can actually be used as a preposition, as well.
Used in a sentence: If you have bad grammar, then people will think you're a moron. I'd rather be respected than considered an idiot.
Try reversing them: If you have bad grammar, than people will think you're a moron. I'd rather be respected then considered an idiot.
The first sentence doesn't change meaning so much as it proves my point. The second sentence, well, it means something entirely different, and you could get your wish if you don't remember this little lesson when you're corresponding with strangers.
Next time....The Great Lying/Laying controversy, plus a bonus feature on The Dark Side of Spellcheckers!