It's not exactly the case that Wikipedia is getting serious about lashon hara. It's more accurate to say the guardians of Wikipedia are taking steps to curtail Motzi shem ra, i.e., lies and disinformation about living people, from being spread through their site. For a discussion of both see Wikipedia.
The editors have decided to closely monitor changes to articles about living people, "Wikipedia to Limit Changes to Articles on People" by NOAM COHEN: "Officials at the Wikimedia Foundation, the nonprofit in San Francisco that governs Wikipedia, say that within weeks, the English-language Wikipedia will begin imposing a layer of editorial review on articles about living people...more..."
We still have our concerns about another abuse of Wikipedia, namely, that it is a primary source of student plagiarism.
We warn students on our current syllabus, You are not permitted to use Wikipedia or any other Internet or digital resources for your assignments.