My first real $ came from a comment, not a post. I know it would be a much more complex data set, but there must be a"bandwagon curve" as well - the point where commenters are most successful.
For instance, this post is 3 hours old right now and it's trending up to 2k+. @recursive has picked up $100 for an intelligent comment. When does a post hit "peak comment"? When is it too late to ride the coattails?
I'm focusing my efforts on intelligent commenting; it feels like that's a more effective angle for me than trying to break through on the front page.