After four years of intricate and widespread filtering, Iran today loosened restrictions on both Facebook and Twitter, allowing open access to the servers. Previously, the services had only been accessible using a VPN or redirecting service outside the country, and many on Twitter commented this was the first time they had ever used the sites without an intermediary. Both Facebook and Twitter have been blocked since the election protests of 2009, when activists used the services as tools for organizing rallies.
The government has yet to make an official statement on the lifted blocks, leading some to speculate that the lapse in filtering is a technical glitch rather than a change in policy. The change is being reported on a variety of ISPs, strengthening the case that the change is national in nature, but the system has gone down in the past without larger implications.
But there's also reason for optimism, as the Iranian political class has shown an increased presence on Twitter in recent months. The change also comes a little more than a month after the election of moderate cleric Hassan Rouhani as president of Iran. Rouhani has been active on Twitter, most notably wishing Jews a happy Rosh Hashanah earlier this month, although the account has never been officially acknowledged.