botnets are going to be all over this... i dont see a way to block them
what about simple spyware, infected browser with corrupted homepages, those sad slaves will give it everything they got...
That's my concern. If websites start embedding the miner then I imagine popup blockers or even the browsers themselves will take steps to prevent the function of this coin. If the wallet/transaction system is separate that wouldn't be the worst thing. But if they aren't it'd remove the main purpose of the coin.