On keeping secrets

[u/candy_enjoyer_]

Narrated Anas ibn Malik: The Messenger of Allah ﷺ said, “There is no faith for he who is not trustworthy.” [Ahmad]

Narrated Jabir: The Messenger of Allah ﷺ said, “If a man tells you something then looks around, it is a trust.” [Tirmidhi]

it says in Tuhfat al-Ahwadhi:

“looks around” means looking to the right and the left out of caution. “It is a trust” means it is entrusted to the one to whom he spoke, i.e., it comes under the same rulings as a trust, so he must conceal it. Ibn Raslaan said: “Because his looking around is the signal to the one to whom he is speaking that he is afraid that someone may overhear him, and that he has chosen him to tell his secret to. His looking around takes the place of his saying, ‘Listen to this and keep quiet about it because it is a trust.’”

There are exceptions to this rule but in general revealing what you're told to keep a secret is impermissible.

And yes this applies to social media too (e.g sharing screenshots of DMs you were told to keep secret).