One problem would be that we don't have syncing that works ACROSS browsers from different vendors. That might be easy to implement technically, but getting comp

One problem would be that we don't have syncing that works ACROSS browsers from different vendors. That might be easy to implement technically, but getting competitors to coordinate is going to be a tough battle. Then there would be little UX issues such as not knowing the name of the user for using in messaging within the apps. You'd need a "Complete your profile" form instead of a "Register" form. However, I do concede that even that would be an improvement over current systems.