He said that these social media platforms create "a public square" and can encourage "political engagement and active citizenship," facilitating "the circulation of independent information providing effective protection for the most vulnerable and publicizing violations of their rights."
However, Francis cautioned that the way that "many platforms work often ends up favouring encounter between persons who think alike, shielding them from debate."
"The proliferation of fake news is the expression of a culture that has lost its sense of truth and bends the facts to suit particular interests," he said, which foments "prejudice and hate."
"The reputation of individuals is put in jeopardy through summary trials conducted online. The Church and her pastors are not exempt from this phenomenon."
Beyond social media, Pope Francis also addressed other technological developments that influence young people today.
"Advances in the sciences and in biomedical technologies have powerfully influenced perceptions about the body, leading to the idea that it is open to unlimited modification," he said.
"The capacity to intervene in DNA, the possibility of inserting artificial elements into organisms (cyborgs) and the development of the neurosciences represent a great resource, but at the same time they raise serious anthropological and ethical questions."
Christus Vivit highlights youth as a time for discernment of one's vocation in the world, which requires a certain degree of prayerful solitude and silence.
Immersion in "a culture of zapping" - moving rapidly between multiple screens or channels - can be a distraction from that essential task, the document warns.
"We can navigate simultaneously on two or more screens and interact at the same time with two or three virtual scenarios. Without the wisdom of discernment, we can easily become prey to every passing trend," Pope Francis said.
Twenty-five year old Laphidil Oppong Twumasi, one of the 36 "youth auditors" in the Synod of Bishops on young people, the faith, and vocational discernment last October, said that she was surprised to discover terms like "influencer" and "zapping" in an official document of the Church.
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"It is easy to understand and is not lost in archaisms," Twumasi said at a Vatican press conference for the document's release. "I must say that there was an effort and a willingness to hear and to really listen to us," she said.
While warning of the technology's potential pitfalls, the pope has also embraced social media and technology himself. The pope's Twitter handle, @Pontifex, has 18 million followers.
Pope Francis recently launched a new app, Click to Pray, which connects smartphone users with a global network to share prayer intentions.
"Seeking the Lord, keeping his word, entrusting our life to him and growing in the virtues: all these things make young hearts strong. That is why you need to stay connected with Jesus, to "remain online" with him, since you will not grow happy and holy by your own efforts and intelligence alone," Christus Vivit states.
"Just as you try not to lose your connection to the internet, make sure that you stay connected with the Lord."