These kinds of changes always start in some sort of localized group or community. While it's wise to not assume that every small movement is going to turn into a large one, it's still worth paying attention to what's going on at the fringes so that you don't get caught with your pants down.

As another anecdote, Facebook has died out amongst my peer group, it used to be heavily used for event planning amongst friends but now it's been abandoned despite no good replacements in the wings because nobody is on Facebook to see your events. Instead we are back to using text messages and emails.