Haven't various sharing models that look very similar to Circles been around for some time?

I have LOTS of friend lists on Facebook. I have Close Friends, Family, Teacher/RA/Restricted, Strangers and then my cohorts broken down by class for various reasons. Now, sometimes Facebook extrapolates from privacy settings for a post and changes my global privacy setting which is annoying but it's trivial to keep an eye on it.

But basically, my geeky posts get my cohorts, my funny posts get posted openly and my rants about drug policy or whatever are blocked from my family.