A Gresham’s Law for Crowdsourcing and Scholarship? by Ben W. Brumfield.
Ben examines the difficulties of involving both professionals and “amateurs” in crowd-sourced projects.
The point of controversy being whether or not professionals will decline to be identified by projects that include amateurs?
There isn’t any smoking gun evidence and I suspect the reaction of both professionals and amateurs varies from field to field.
Still, it is something you may run across if you use crowd-sourcing to build semantic annotations and/or data archives.