"Anonymity can encourage contributions, rather than discourage them."

Didn't I say so?

There are two other key contributors to Wikipedia’s success with attracting its own contributors: Wikipedia offered low transaction costs to participation, and it de-emphasized the social ownership of content. Editing Wikipedia is easy, and instant, and virtually commitment-free. “You can come along and do a drive-by edit and never make a contribution again,” {Benjamin Mako] Hill pointed out. And the fact that it’s difficult to tell who wrote an article, or who edited it — rather than discouraging contribution, as you might assume — actually encouraged contributions, Hill found.

Nieman Journalism Lab: The contribution conundrum: Why did Wikipedia succeed while other encyclopedias failed?