Karma's based on the average of other peoples ratings of your posts. Your own post rates at your current average.
Therefore, me thinks the higher the post count the harder to shift your rating. (ie posting away to yourself, while fun in its own scatching an itch way way dosen't help at all). Plus life on the cusp is very confusing all the rounding factors its way in...bahhh
Ahh, death by averages -- you gota love it :)
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