Wikipedia is 20
I am surprised that the comments haven't mentioned the role of SEO in Wikipedia's growth and defensibility.Wikipedia's habit of deep interlinking helped it rank back in the early aughts when the SEO rules were rather simple. Add to that the subdomain-driven localization strategy and many other moves that were considered SEO best practices back in those years when the on-page factors used to matter.But that was just the start. Wikipedia killed it in SEO when it was easy to do so, but it also did one other thing that most SEO-driven sites (eg: About) didn't do correctly - it cared deeply about the content quality and also resisted to run ads (anyone remember Jason Calacanis' articles on how they are leaving $100m on the table? See [1]). So when Panda came around, Google correctly rewarded Wikipedia with #1 rankings for over 50% of its terms (!!), and Jason Calacanis had to shut down Mahalo which got destroyed by Panda.Wikipedia's dominance continues because it's basically impossible to overcome its lead in inbound links and domain authority. Add to that a surprisingly under-the-radar company culture which has avoided any major blow ups despite its community wielding so much leverage over the world's education and having to make a lot of difficult calls on a daily basis.Well done.[1] https://calacanis.com/2006/10/28/wikipedia-leaves-100m-on-th...