The other nice thing is that Gmail hides the excessive quotes if people don't *snip* them, and colors the relevant quoted text it does show, so you can easily tell what's being reposted (or rehashed, or dead-horsed).
That's once of the best features. It does get a little confusing, though, when someone says something very similar to what they're replying to and gmail thinks part of it is a quote and you end up with half a paragraph in purple...