[fluxquanta]

You can't neglect the fact that while facebook's outward appearance is "social media site", which may indeed be on the decline, they do a lot of work behind the scenes just to manage such an incredible amount of data.

I could easily see facebook surviving long into the future in a similar way to IBM -- with a focus that is shifted from what made them big player, but still doing valuable work (and making money) in the tech "sphere".