focusing on credentials might well reduce contribution; even in its absence, the most common reason my brilliant iconoclastic US friends give me for not writing about <whatever they're reading / studying> in Wikipedia is that they are "no expert" on the subject.
--SJ
That is, my *two* brilliant iconoclastic US friends. People I would have thought would glom onto the notion of adding to Wikipedia as a natural one... but only two; your mileage may vary.
In a world that is moving to greater transparency, wikipedia is, in fact, a model. Consider being able to earn one's degree by writing on wikipedia. Edit articles, have a thesis advisor review contributions, and score credit appropriately. Adding bibliography, annotation and other activities which "polish" wikipedia would be part of assignments.
Indeed. and encouraging people to write more about their interests, background, and references/sources is a very good thing in terms of transparency. But explicitly making it easy for others to judge you based on that, is a bit like making "edit count" a metric of community activity. It encourages fraud and inflation, and discourages more accurate and subtle metrics.