lkcl: Ratings and reports are explained in the Advogato FAQ, by the way. One thing I can't tell whether you realized or not: The report at /rating/report/lkcl does not show what other people think of your diary. It shows what you (and the people you certified) think of other users' diaries.

The lumpiness of the histogram is because most users don't use the full range of ratings. And since confidence scores fall off exponentially by network distance, your confidence-weighted histogram will be skewed toward ratings given out by yourself and people you directly certified. For example, I tend to rate most diaries between 4 and 9, so I expect my report to be skewed toward those values.