[emw]

That point is worth making.

Sociological issues among established Wikipedia editors do contribute do lower retention of desirable new editors, but like Animats I suspect Wikipedia's comprehensive coverage is a significant factor (perhaps more so). It's simply less appealing to do curatorial work than to make large additions to major articles like "Genetics" or "France".

Which factor contributes more to Wikipedia's active editors drop-off, sociological issues or encyclopedic completeness? Has anyone looked at that? I'd be interested to see an analysis of how the trends in the notorious graph at http://commons.wikimedia.org/wiki/File:Enwp_retention_vs_act... correlate with word count and reference count in important articles.