The Wikimedia Foundation reported last week on a professor at Auburn University, Montgomery, who included his Wikipedia editing history in his tenure packet:
“I’ve written articles in many areas, and in many cases I could show my colleagues what I had done in their field,” Michel [Aaij] says. “I’d like to think that by now most of them have a favorable opinion of Wikipedia. Let’s face it: Guillaume de Dole, now a Good Article, there’s no database entry or encyclopedic article anywhere that compares to the Wikipedia article on that poem (and I realize that that says as much about Wikipedia as about the anywhere else).”
He teaches in English and Philosophy. Personally, I view this as no different from counting solicited encyclopedia entries. These are not counted as highly as original research effort, but they do factor in as evidence of professional research activity. Obviously you don't want to tenure somebody whose only research contributions are derivative, but that's not what this story is saying.
I wouldn't contribute to Wikipedia because the editing process does not sufficiently protect expert contributors. But Wikipedia has a far greater public impact than any printed encyclopedia, and providing accurate content is a service that for many topics requires substantial expertise. Universities would be wise to find ways to recognize this kind of service and connect their scholarship to the broader public.