A more difficult challenge is predicting karma on your top level posts.

That is difficult, and one of the reasons I'm very hesitant to post. (Luckily, my first three posts were "important" enough to me that I almost didn't worry about their scores before posting; as for the fourth, I somehow managed to predict the score almost exactly correctly.)

My predictors in this area tend to be way off the mark. For this post, my guess is between +4 and +20. Reasoning: I don't see how it could get over 20 unless it gets promoted and the concept surprises readers; 4 seems like a solid guess for "interesting, uncontroversial, but not groundbreaking."

I've been thinking it might be useful to establish a consensus on the "meaning" of various levels of post karma. Here's my top-of-the-head-suggestion:

0-10: Acceptable

10-20: Solid

20-30: Good

30 - 40: Quite Good

40+: Outstanding

100+: Unheard-of Stupendous Brilliance

I'd be curious to hear how this compares to others' views of post scores.