What web developers should be doing is testing for features, not UA-sniffing. In this case, to the extent known, it appears that Skype for "web" functions on Fi

What web developers should be doing is testing for features, not UA-sniffing. In this case, to the extent known, it appears that Skype for "web" functions on Firefox and Safari without any issues, if you change the UA. (It would also be nice if web sites provided graceful degradation if features are not available, but that doesn't even appear to be necessary here.) Also, as others have pointed out, do you really want to live with a Chrome-only monopoly? For instance, do you value having a full-featured Adblocker? Recently, Chrome was considering withdrawing some of the extension APIs needed for one (they've since partially, though AFAIK not completely backtracked). I won't pretend to have an insight into Google's internal politics, but I think it's plausible that the existence of a privacy-friendly alternative such as Firefox (apart from obviously being valuable in itself for its users) discourages Google from being too privacy-hostile for fear of users eventually getting fed up and switching (or it provides an argument for the Google engineers, the vast majority of whom want to be user-friendly, for resisting introducing more egregious privacy violations).