Mobile-friendly is going to matter for pretty much everyone. An example: a lot of times when I’m using Twitter I’m on my phone, killing time while I wait for an appointment or a ferry. If I follow an interesting tweet and end up on a site I can’t see well, I just leave. Or if I get to a site that is interesting and I don’t see a place to sign up for their newsletter, I don’t.
If your site looks barely decent on a mobile screen, you might just need a mobile-friendly intro screen that tells mobile visitors what your site is all about so they know they’re in the right place: this will make them more likely to come to your main site and go through the effort of looking around.
