[acangiano]

Wikimedia Foundation does the same to support Wikipedia. Check out the list of Sustaining Corporate Donors: http://wikimediafoundation.org/wiki/Benefactors

Unlike W3.org, these aren't nofollow links. So they are outright bought for anchor text goodness and PR juice.

[thegyppo]

I wouldn't be surprised at all if Google manually stops PR from passing from this page.