[oldcynic]

If, as seems to be the case, Instagram is the popular destination to migrate to will Facebook be too bothered by a drop in Facebook numbers? Sure some will go elsewhere, and block enough FB tracking to disappear entirely.

Instagram, of course, will allow Facebook to keep tracking and advertising to people just fine. No doubt they've already linked Instagram and FB identities wherever possible.

So all that remains is to see if ads work as profitably on that platform. If they don't there will no doubt be an Instagram redesign for that.

[gaius]

Instagram, of course, will allow Facebook to keep tracking and advertising to people just fine

There aren’t many “like/share this in Instagram” buttons around the web.

[utellme]

That's the key idea - they will continue to do M&A to get advantage in tracking and exploring user behavior.

Instagram is just data provider.