Hi,
http://wikimediafoundation.org/wiki/Wikimedia_visual_identity_guidelines states that approval is needed for letterheads and business cards, which seems to imply that casual use of the logo doesn't require approval, nor does anything on that page imply that it is.
Additionally, that logo does meet the requirements as far as I can see, 60% black subtext, at 60% of the size of the main text, in DevaVu Sans. (it seems GIMP decided to make it 40%, the attached version corrects this, and if you're referring to the spacing, the version I downloaded didn't have that much spacing, and I interpreted the guideline as stating there should be that much of a margin in printed versions)