I'd have to say that it's probably an Islamic fundamentalist ploy. If I had to guess, I'd pin the blame on the Iranians. The internet is absolute murder for them -- there's no way for them to control the flow of information from the infidels. It reminds me a lot of the story a couple of years back, about Iran cracking down on satellite dishes.
Now ... as to "why now?" That's a pretty question. I'm thinking it's an internal thing: that Ahneedajihad is about ready to go Taleban on the Iranian people.
What do you mean, no way ? The Iranian gov’t controls/owns the Iranian telco companies. Just like the Chinese, I’m sure they filter whatever they want to and deny connectivity whenever they want.
The only thing they might not totally control is satellite, and that would not be available to the average Iranian in any case.