There is rationale for building a web site that’s mobile only. There are many, many things that don’t adapt well from a mouse-and-keyboard interface to a phone interface. However, the fact that some things don’t adapt well to the phone does not mean that everything must be re-built for the phone.
If we look back in time, we see that some large sites (Google, Yahoo, Wikipedia) had mobile specific sites for all our tiny little dumb phones pre-2007. These were the days of the WAP web (remember that?), and they were dark days indeed.
Things were bad for mobile, but thankfully, Apple came to save the day! I’m quoting from the 2007 keynote that introduced the iPhone and the modern smart-phone to the world. In Steve Job’s own words:
“Rather than just give you the WAP version of [the website], or a wrapped version of [the website], we’re showing you the whole website.”
Upon hearing this the world rejoiced because now we had mobile devices that could view the “real” web, and no one ever made a mobile-specific site ever again.
Except not. We’re back at it, building a mobile-specific web. Sometimes, it is appropriate to adapt a totally incompatible interface to a mobile specific one. But, that “sometimes” seems to have slowly shifted to “nearly always”.
Let’s look at an example; here’s Github in the desktop on the left, and Github on my phone on the right:
Let’s see on my phone, I want to go view the wiki – oh wait. I can’t.
Well, maybe we can go see the releases, see if any updates are – oh wait. I can’t do that either.
Stop it. Really, stop it. Be like Steve; show me the full web, since the modern smart phone was literally built to use it.