It was Michael Mann, the spokesman for EU foreign policy chief Catherine Ashton, who broke news of the deal on Twitter while quoting his boss:
Mann had updated the public throughout the talks with his tweets. He also tweeted several times in Persian.
Iran's Foreign Minister Javad Zarif also used Twitter to announce the agreement to his followers:
We have reached an agreement.— Javad Zarif (@JZarif) November 24, 2013
Zarif later also updated his popular Facebook page, where he wrote that the negotiations had concluded successfully.
"Uranium enrichment was officially recognized, activities will continue and sanctions are going downhill," he wrote, adding that national unity was more necessary than ever.
Social media appear to have been among the primary sources of information for tech-savvy young Iranians who had stayed up all night to follow the news about the talks.
You can read the White House's "fact box" with details of the deal here.
-- Golnaz Esfandiari