Frankly, I don't think flattening the contribution graph is possible unless you put a cap on how much people can contribute. Most online communities of any kin

Frankly, I don't think flattening the contribution graph is possible unless you put a cap on how much people can contribute. Most online communities of any kind follow a power law with a small number of heavy contributors and many more occasional contributors and "lurkers". This isn't a consequence of barriers to contributing but of human nature.