From the Search Engine Journal, All Wikipedia Links Are Now NOFOLLOW:
I blogged about the Wikipedia Issues with SPAM and the discussions about the use of NOFOLLOW for ALL external Links from Wikipedia. It was done, finally.
As of now are all outbound links from the english Wikipedia Site using the NOFOLLOW attribute, no exceptions.
No matter where you place it, Article Page, Talk Page, User Page, Project Page, whatever. No Link will get any credit at the major search engines.
What does this mean for you my fellow bloggers? Well, you still get that link if your site or blog has been added as an external source, along with it the referral traffic. That’s about it actually.
What does this mean to the SEO guys? Well, they could start by
firing letting go everybody in the Wikipedia Contributor Department.
Does it matter? Not much really but if you (partly) live off PR juice and Wikipedia link loving, you’re basically screwed. Naah, just kidding. Besides, not all of the big search engines follow the nofollow tag.