Last time I checked out shiny (about 8-12 months ago) it was still useless beyond the most trivial examples. Building an actual website that would be public facing seemed like a horrid idea at the time. Have they really come that far in such a short time?

Personally if I wanted to use R I could just interface with it from another language (Python, .Net, Java etc.) I haven't played enough with R recently to make an informed opinion on the current quality of its network libs and framework stack however it seems like an interesting gamble (that's paying off for you all?) given where the focus of the R community has been (statistical programming rather than general use) and statements on the front page of "No web development skills are required."