Tithes and Offerings: What are they, and what are they good for?

Many people mistakenly do not distinguish between tithes and offerings - I myself thought that they were the same thing for most of my life! The usual picture that people get when they hear either of these words is an "offering plate" being passed around in a church on Sunday with people putting in various amounts of cash, and the ideas of tithes and offerings are one and the same. This modern tradition is not according to biblical understanding.