So is Iran behind this? The targets - Yahoo, Tor, Wordpress, Google (in Iran!) and Baladin (Iranian blogging service) - are pretty strong indicators. None of those are financially lucrative targets in themselves, or much good for spammers who aren't targeting Iranians.
Having read about some of the stuff the Iranian government got up to in the last three decades, they seem to be rather a law unto themselves. It's rather worrying that they're now targeting online infrastructure.