Very timely post. Full disclosure : my current project [1] deals with archiving content from social network, and we're considering adding more things to import from facebook. The friends list example from the article is a good one :

  As for my friend list.. well.. It's all in Json format..
  So now you can essentially use the power of your brain to think how your friend looked.
  If you can't, well then you probably weren't friends anyway. Sorry.

I'd be interested in your experiences either in leaving facebook, or about things you'd which you could have saved

[1](https://www.getkumbu.com/)