The United States has eased sanctions on Iran, Sudan and Cuba in an effort to increase the use of the internet and social networking sites there, and support opposition groups.
The US treasury says it wants to make it easier for people in the three countries to communicate with each other and with the outside world.
US technology firms will now be allowed to export online services such as instant messaging and social networks, the BBC reports.
Opposition supporters in Iran used social networking sites and services to organise protests after the country's disputed presidential poll last year.
The US Treasury says exports would be allowed of services related to web browsing, blogging, e-mail, instant messaging, chat, social networking and photo-sharing and movie-sharing.