Embeddable Miner for Websites - This idea for Bitcoin done?

[BitcoinPorn]

The dream of having Wikipedia run off the electricity of the users donating it to ensure things are kept ad free, and the only time you'd be paying to use the site, is obviously when you are on it.    There was Bitcoinplus.   KRAD miner I think.   The great Bitp.it pool started out with that.   With the difficulty the way it is, is attempting to find any amount of true usability for an online Bitcoin miner over?

Do people feel that this type of technology will only be abused?