We're reluctant to add threaded comments to Xanga.

Our experience with threaded comments (off of Xanga): they can be confusing, and often lead to off-topic discussions.  Being off-topic isn't the real problem though - the real problem is that threaded comments often include personal attacks.  A commenter using threaded commenting is much more likely to respond to another user rather than to the topic of the post.

It's kind of like how lawyers at a trial are only supposed to address the judge.  If the lawyers could actually talk at each other, they'd probably just yell at each other.  This could very well threaten civiliazation as we know it.