[codetrotter]

In the bottom left of the compensation graph, there is a non-zero percentage of people earning less than 0 USD per year. I guess they used a smoothing function fit to the data points. The alternative is that some people are paying their employers some dollars for the privilege of working for them :p

[gus_massa]

There are some weird waves at 400k, 500k, 600k, ... It's probably an histogram diguised as a line graphic.