Observing the progress in Iran's nuclear program which may be directed towards Israel. US and other powers decided to impose all kind of economical blockage and isolate Iran from the globalized world. US considers Iran's nuclear program a threat to itself and so it took various steps for installing an anti ballistic missile system in Europe which can shoot down any incoming missile towards US.
Many websites also followed suites of blocking Iran. Hotmail and Yahoo were some of them who blocked Iran from accessing their webmail in 2007, recently few months back news were coming of Iran thinking of blocking Gmail. Iran was the country which blocked facebook before elections and lifted the ban when the elections were over, this was to prevent opposition party becoming popular among the citizen.
US had shown its concern over the Iran-Pakistan-India Gas pipeline, US had also made India vote against Iran in IAEA which was something against the old friendship of India and Iran. In the reward India got a nuclear deal.
Iran expects that it will be ready to resume talks from September 1st with some conditions. They said the six - (the United States, China, Russia, Britain, France and Germany) - must answer whether the talks are aimed at "engagement and cooperation or continued confrontation and hostility towards Iranians."
The question is solid and obvious, due to blockage Iran has suffered a lot. Israel is supposed to be developing nuclear weapons secretly as well, as they believe in Iran's case, but Israel never received such treatments by the world community. The concept of nuclear disarmament is good, but it is not being applied properly. If you think only you can keep nuclear warheads and no other countries can, then there is something wrong in the policy. Those who developed first should destroy first and then the others must follow.