Discussions regarding the implementation of “intelligent” filtering have proliferated Internet policy discussions within Iran. “Intelligent” filtering is a process whereby they filter select content on a social media platform, rather than the entire site. Our recent research  covered the extent of this program on Instagram. In response to “intelligent’ filtering discussions, Abdolsamad Khorramabadi, an advisor to the Committee Charged with Determining Criminal Content  (CCDOC) told Tabnak news on May 5, “Facebook will definitely not be included in this type of [smart] filtering, and will remain completely blocked.”
Commenting on the policy on May 14, the New York based International Campaign for Human Rights in Iran  stated,
The continuation of the Facebook ban reflects the profound fear with which Iranian officials view social media networks, which have proved enormously popular in Iran, particularly among the younger generation.
Previous Iranian discussions of “intelligent” filtering on social networks never breached how the government would implement this program on networks that use HTTPS protocol, such as Facebook. The only known implementation of this program has been through the unencrypted Instagram API.
For further information on this announcement see the International Campaign for Human Right's recent report: “Iranian Officials Re-Affirm Facebook Will Remain Completely Blocked in Iran.”  For technical understanding of “intelligent” filtering, see Frederic Jacob's Instagram testing and analysis on GitHub .