Since Wikipedia is mainly controlled and operated by volunteers, Larry Sanger (a former founder of Wikipedia.), left because he believed it should "give more authority to experts".
The statistics shown in the article show how popular Wikipedia is for such an "unreliable source". I believe Wikipedia is so successful because people have constantly relied on the information of others for centuries.
I'm not sure why Wikipedia wouldn't want to advertise their website. maybe because 90% of the world's population has already used/heard of it already.