Wikimedia's thorough discussion on the pro and cons <a href="https://en.wikipedia.org/wiki/Wikipedia:Funding_Wikipedia_through_advertisements#Arguments_against_adverts" rel="nofollow">https://en.wikipedia.org/wiki/Wikipedia:Funding_Wikipedia_th...</a>
Maybe they would go down to 16M page views per month and somebody would jump in the void they leave.<p>Wikipedia was successful because it was (and is) free. I remember competitors with a paywall failing one after the other. Remember Microsoft Encarta? CD ROM first then the web. Retired in 2009 when Wikipedia was much smaller than now
<a href="https://en.m.wikipedia.org/wiki/Encarta" rel="nofollow">https://en.m.wikipedia.org/wiki/Encarta</a>