" If you want to see the snippet, it is there all the time," he said.

2. He's into space

Mr Lee checks out the Astronomy Picture of the Day. The site, which is by the United States' National Aeronautics and Space Administration (Nasa), posts an astronomy-related photo each day.

"Every day there is a picture, a nebula, a supernova, the sun, rings of Saturn, something like that," he said.

The site has been managed by professional astronomers Robert Nemiroff and Jerry Bonnell since 1995.

3. He follows mathematics blogs

Mr Lee told Mr Singh that he "sometimes looks at blogs by mathematicians to track what they are doing".

One of the blogs he follows belongs to Australian-American mathematician Terrence Tao Chi-Shen, a professor at The University of California, Los Angeles' (UCLA's) Department of Mathematics.

"He covers all sorts of things," said Mr Lee. "Usually I get lost after the first two paragraphs of his post but it is interesting to know what he is working on."

Professor Tao blogs about his research and expository papers, and invites discussion on various mathematic problems and issues.

4. He tracks photography websites

Mr Lee is known to be a fan of photography, often posting pictures he takes on his social media pages, so having photography sites on his to-visit list is not a surprise.

He browses photography pages to get inspiration.

"You pick up ideas looking at what people do, how they take the pictures. Some hints, some sense of what you are looking for and how you analyse a scene," he said.

"Now when I look at pictures, you do not just say it is very pretty. You figure out where his leading lines are, where his focuses are, whether he put it on the one-third line or not and all sorts of technical things."

He likened the process to wine appreciation: "It is like wine, oenophiles drinking wine and activating the brains instead of just the taste buds. But it is fun."

5. Paid for a little-used Spotify subscription for about two years

He shared that he has iTunes, but does not use it very often. He let on that he tried Spotify, but did not use it much.

"I tried Spotify. I signed on and from inertia, I left it on for about two years and I was paying them $10 a month," he said. "I will tolerate the advertisements every 20 minutes if I decide to listen to them again."

6. He prefers physical books, but uses a Kindle for convenience

Mr Lee reads mostly on his Kindle, "because it is much more convenient than carrying a book".

However, he lamented that the reading process on a Kindle device is not absorbed as well as with a physical book.

"With a physical book you have a sense of where you are, how far to go, where they fit together. You can flip back, you can side-line," he said.

The Kindle is not the same, he said, but the convenience makes it worthwhile.

He has previously shared his book picks with his Facebook followers.

In June last year, he wrote about three books he read while on his trip to the Middle East: Ari Shavit's My Promised Land: The Triumph And Tragedy Of Israel; Operation Thunderbolt, by Saul David; and A Rage For Order by Robert Worth.