> I worry they will begin using more and more of the (now historical for almost two decades for some accounts) data they have to open new revenue streams

That data ain't worth jackshit. If it actually was, Facebook would have tapped into it long ago when they were more directly beefing with Google.

Plus, the older data gets, the less useful it is. No advertiser cares what 21 year old, Joe, was into now that he's in his 30s and only occasionally posts baby pictures.

As it stands, Google has shown that knowing consumer habits always trumps what you are writing on your Feed/Wall.