Here's a hypothetical (but common) situation:
1) User receives an email with a website link.
2) User is on a smartphone.
3) User clicks on link and opens website in mobile browser.
4) User is shown a website that does not work at all on mobile browser.
5) User unsubsrcibes and deletes the email.
6) User has a bad feeling like their day isn't going very well.
How could we do this differently?
1) Website owner has a website which is optmised for mobile devices or a responsive design which works fluidly across devices.
2) User clicks link.
3) User engages with the site and has a lovely experience which makes them smile.
4) User reads your emails again in the future.
It is crucial that the mobile experience of your site is well thought out. What are the crucial tasks users are looking to do on your site? How can you allow them to do this as easily as possible on their mobile? What features or content might be a distraction?
Most of our recent projects have included specific requirements for user experience on mobile devices. Temando, for example, wanted primary content to be the focus by stripping back less important content. Daniel Ferris wanted gallery browsing to be intuitive and slick. We used a responsive design which resizes nicely across devices and also implemented some nice swipe gestures for image navigation.
If you are starting a new project consider the mobile experience right from the start as part of your brief (allow some budget). If you have an existing site that has not been optimised for mobile it is possible to scope this out and build it in. Check your site on a few different devices now and see if you think the experience is up to scratch. Is it? Working well on mobile is no longer optional.