This question is essentially about my subjective probability for Douglas Knight's assertion that "Clippy does represent an investment", where "investment" here means that Clippy won't burn karma with troll behavior. The more karma it has without burning any, the higher my probability.

Since this is a probability over an unknown person's state of mind, it is necessarily rather unstable -- strong evidence would shift it rapidly. (It's also hard to state concrete odds). Unfortunately, each individual interesting Clippy comment can only give weak evidence of investment. An accumulation of such comments will eventually shift my probability for Douglas Knight's assertion substantially.