"They can be cocooned in information that reinforces their current biases", Obama said.
The programme is focusing on issues such as the armed forces, mental health, youth crime and climate change - a cause his father also champions.
Britain's Prince Harry has avoided opening up a diplomatic rift between the British and USA governments over the guest list for his wedding to Meghan Markle, saying plans had yet to be finalized.
Obama, who was interviewed for an edition of the BBC Radio 4 Today program guest edited by Prince Harry and broadcast Wednesday, said it was a challenge to make the most of the opportunities provided by social media.
It is the 14th year public figures have been in control of the Today's output between Christmas and New Year.
Other guest editors this week include a robot, Bletchley Park code-breaker Baroness Trumpington, Tamara Rojo of the English National Ballet and poet and novelist Benjamin Okri.
The programme is being presented by Justin Webb and Sarah Montague.More news: Netanyahu: 'God Bless' Guatemala Over Jerusalem Move
Prince Harry, 33, said he had an "amazing time" at Christmas - Ms Markle "really enjoyed it and the family really loved having her there" although there were "plenty" of family traditions he needed to explain to her.
Yep, Prince Harry has now talked about how he and Markle spent the day at his brother and sister-in-law's, that's the Duke and Duchess of Cambridge to you and me, "running around with" his nephew and niece Prince George and Princess Charlotte.
The interview was recorded in September in Toronto, when Obama was in Canada to attend the Invictus Games, a charity and sporting event created by Harry to honor wounded soldiers.
Another section saw Met Police Commissioner Cressida Dick interviewed.
Prince Harry or William?
The prince opened the discussion by saying: "This is the first interview you've said "yes" to doing since you handed over the reins", to which Obama replied: "that's true". "I'm talking about us all because everybody does that".
There were also light-hearted exchange between the prince and former president. "Things aren't as simple as they've been portrayed in whatever chat room you've been in", he added. "There is nothing, not a single thing, that's more important to the future of America than whether or not young people all across this country can achieve their dreams", Obama says in a speech included in a 60-second YouTube video.
Obama did not mention US President Donald Trump by name during the interview, which he said was his first since leaving office.