Because Sitefinity Page Template can be based on ASP.NET MasterPages, mobile-friendly templates are certainly possible. You control most of the HTML markup that is applied to your website, thus if your Page & Widget Template are mobile-friendly, then your website is mobile-friendly. In fact, the Education Starter Kit (included in the Sitefinity SDK) uses HTML5 features to create a responsive website:
All of this is possible today. However, I've also seen some internal prototypes that bring these responsive features directly into Sitefinity's toolbox. However, I don't think we've publicly announced a release schedule. It seems likely to me that these will appear inside Sitefinity in the next few months.
Either way, there is no reason that you can't create a mobile friendly website with Sitefinity today. However, in the months ahead you can expect this to get even easier.
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