During this past week, I saw a facebook status that used the word "than" instead of "then."
According to this website, http://www.elearnenglishlanguage.com/difficulties/thanthen.html, "than" is a conjunction and is used in comparisons. For example, Sally is stronger than Maggie. In this sentence we are comparing Sally's strength to Maggie's.
"Then" can have multiple meanings. The most common meanings are a point in time, such as I wasn't ready then, and next or afterward, like in the sentence I ate breakfast then I took a shower.