I have wondered this for a long time now,but it came up again when my mother asked me: "Why does facebook open sometimes in the browser if i downloaded the app ?" So i thought is this a technical question and tried to explain her links work,but in the middle of the explanation i wondered..why does facebook even have a website at all? Why is this so confusing to new users? What is the point of adding more confusion-as most people agree the dedicated app experience is usually superior,and the mobile website uses a completely different design!
The question isnt really about facebook in particular,since there are multiple services which have a mobile website in ADDITION to their own application. Most of these apps are supported on most mobile operating systems so saying "compatibility" is not an acceptable answer in most cases.
I would like some insight on how this works in a UX perspective,this is NOT a marketing/design question