Wikipedia launched that in July 2013 in response to rising web traffic and the existing site not working well on mobile browsers. That was preceded by Wapedia,

Wikipedia launched that in July 2013 in response to rising web traffic and the existing site not working well on mobile browsers. That was preceded by Wapedia, an independent site that started in 2004 to provide a reformatting proxy for mobile use: https://en.wikipedia.org/wiki/Wapedia https://en.wikipedia.org/wiki/Wapedia The basic answer is that early on the tooling wasn't there to support very difference devices from the same HTML. You could try tricks to detect mobile devices and serve different content. But it was much easier just to let people decide which they wanted. I haven't kept up, but I know the tooling keeps improving, so I expect that few people today are creating mobile-specific URLs, and that the existing ones will go away in the long run.