Question was "What would the world be like if everyone was like you?" People took a couple of very different scenarios from that: either physical identity (a world of clones, body and mind) or philosophical identity (a world in which everyone shared your values) or both (because of confusion between those two, or some mind-body identity intuition), or even neither (because focussing on behaviour only). One friend asked if Uma Thurman would have a beard like him, a line of inquiry which got obscene very quickly.
Most people assumed that 7 billion people would morph overnight, and that the great new Them would have to deal with the world as it is currently, rather than any other laws of nature being bent to make e.g. perfect social justice possible.
The intuition pump was for people to report the things they see as essential about themselves. (Can someone have your exact values or personality without also having your body, rocking your style?)
What would the world be like if everyone was like you?
HP: Heaven, due to lack of you.
BM: Fucking awesome!!
QB: A lot quieter.
MJ: All barbers would go out of business. The hi-tech economy would collapse as everyone moved to the supply side. There would be famines and flooding, since no-one could be bothered doing anything so boring as civil engineering. World leaders would legalise all drugs, but the market would collapse because of almost no demand. There would be no war - only melodramatic internet posts. And every shoe would be urinated upon!
Eventually society would stabilise, but to a flat and apathetic state. Beards would be filled with semen wherever you went. No-one would work, other than to reprogram the food and building machines. There would be no art, because everyone would already know that they are altogether MJ, as one beard growing into eternity. Wait, will Uma Thurman go around in a lumberjack shirt with a beard, drinking beer and making Linux puns? (...)
Everyone will be sterile and there will be no children. We will clone both short and tall women and tall dudes in vats. Everyone will be promiscuous. All tall women will fancy short women and likewise all men will fancy short women. Other couplings will occur due to desperation and alcohol use.
(He sensed the question's ambiguity.)
MN: Less productive, more creatively based and less of a sense of capitalism - if that makes sense. I think the world would have potential that would never quite peak past mediocrity. That's okay though. - There's worse things.
JM: Ever see The Tale of the Princess Kaguya? Well, the world would be the Moon Kingdom from that.
CP: You know the blood ocean lizard orgy hallucination from Fear and Loathing? (BLOOD FLOWS FREELY onto the floor. DUKE keeps his voice low: Order some golf shoes. Otherwise, we'll never get out of this place alive. It's impossible to walk in this muck -- no footing at all...)
JW: It'd be crap because all would be knowable. I suppose it could be ignorantly blissful too.
LB: It would see everyone looking in bins - but there's no food waste cos everyone's already taken it. Buses would be littered with rolling papers and apple cores, if there were even buses which there wouldn't be because I can't drive and everyone is like me. Everyone is intoxicated but there isn't any random drunken violence either. Thankfully everyone is not like me.
CWR: Most of the economy would be devoted to practical jokes and deception. They would survive because they all like sustainable farming. The naming system would be based on feats like in fantasy novels: R the Inept, R the Even More Hilarious.
The general answer, applicable to all, is: "the economy would tank, life would be very very hard, and most of sexuality would evaporate".