This Browser based miner would be a great thing to introduce people to Bitcoin mining.
I suppose it would have to say, "OK, you're mining now, although you aren't really earning anything significant", and the person might earn a share or two after they leave it on for a while. Just having crossed the mental hurdle of being successful in mining (even if negligibly) helps promote BTC.
Yup, that's precisely what I'm going for, introducing people to bitcoin and increasing the popularity. Later on hopefully I can add a way for them to earn more significant amounts.