NEW DELHI -- When former U.S. President Barack Obama spoke to a leadership forum in India's capital on Friday, he never once used the words "Donald Trump" and was careful to avoid any direct reference to his successor in the White House.

Yet Obama made plenty of veiled references, from climate change to the perils of using Twitter. The responses often drew laughter from the audience at the which was part of a three-country tour Obama is undertaking in one of his first global outings as a private citizen after leaving office.

Here's what Obama had to say:

SOCIAL MEDIA

Obama said he uses spellcheck and punctuation.

"Which my daughters think is odd. They were explaining to us how if you put a period at the end of a sentence it sounds harsh. I said, 'No, that's English. That's how you know the thought is finished."'

He said he sees people getting in trouble for their tweets, and says they should follow the old advice of thinking before you speak: "Think before you tweet," Obama said. "Same principle."

He said social media is a powerful tool, for both good and ill. "And look, I've got 100 million Twitter followers. I actually have more than other people who use it more often."

(For the record, Obama has 97 million Twitter followers and Trump has 44 million).

CLIMATE CHANGE

Obama said he could have a debate about climate change with people who said fossil fuels were necessary for growth in poorer nations like India or people who said humans should adapt. But he said he couldn't debate with people who claimed it wasn't real.

"If you're saying it's a hoax, then there's no way for us to bridge our differences in a constructive way," Obama said.

Trump has previously called climate change a hoax.

Obama praised India for helping forge the Paris climate agreement, which he signed last year but which Trump said he planned to withdraw from.

"It's an agreement, even though we have a little bit of a pause in American leadership, that is giving our children a fighting chance," Obama said.

LEADERSHIP

Obama said politicians usually reflect public opinion.

"And so if you see a politician doing things that are questionable, one of the things as a citizen is to ask yourself 'Am I encouraging, or supporting or giving license to the values I'm hearing out of the politician?"' Obama said. "Because frankly, politicians tend to be more of a mirror and more of a reflection of forces in the society."

OSAMA BIN LADEN

Obama was asked if Pakistan was hiding Osama bin Laden or was unaware of his presence and therefore incompetent ahead of the U.S. raid in May 2011 that killed the al-Qaida leader at his compound.

"We had no evidence that the Pakistan government was aware of bin Laden's presence there," Obama said. "That is something, obviously, that we looked at. I will leave it to you to characterize beyond what I just said."

DUCK OR TRUMP?

Obama was asked who reflected the real America, Donald Duck or Donald Trump?

Obama didn't answer directly. He said Americans could often be kind and noble, and at other times cruel and shortsighted.

"It is just this cacophony of life. And it throws up all kinds of variety," he said. "And there are political trends in America that I don't agree with or abide by, but I recognize as part of a running thread in American life."

He said he took heart from the fact that the trend lines of America and the world were heading in the right direction when it came to inclusion, health, education, equality and kindness.

He said that despite the bad news people hear every day, that when it came to having a good life, right now was the best moment to be born in all of human history.