Since 1979 the United States has not had an embassy in Iran. As such, it has always been more difficult for Iranian immigrants to come to the United States because they could not access consular services within their own country.
Although the United States still is not able to maintain an embassy in Iran, it has attempted to do the next best thing to help the Iranian people. The United States has opened a “virtual embassy” on the website: iran.usembassy.gov/about-us.html. The virtual embassy (which I think is the first of its kind) is meant to provide as much information as possible to Iranians seeking to travel to or immigrate to the United States.
Although it has no official recognition from the Iranian government, hopefully it will better serve the United States and the Iranian people.