In 2008, Gary Vaynerchuk made a Youtube video called "Facebook should be worried about Twitter."

"It was like, 'Why am I starting to use Twitter more?' It wasn't this big grand statement. It was one person's point of view," Vaynerchuk told Business Insider's Alyson Shontell in an episode of the podcast "Success! How I Did It."

The CEO of VaynerMedia had become something of a YouTube celebrity — today, he has over 639,000 followers on the site, not to mention millions on Facebook, Twitter, and Instagram — and the video picked up steam in Silicon Valley.

Soon, Vaynerchuk received an email from startup investor and founder Dan Morin: Would Vaynerchuk be interested in giving a talk in Palo Alto on the subject?

"I'm like, 'I'm going to Palo Alto next week' — which I wasn't," he told Shontell.

He continued:

"I gave a talk about consumer behavior. I didn't even know but Mark was in the audience. He came down. He was like, 'You want to have dinner tonight?'

"I'm like, 'Yep.' I had a flight that night. I clearly canceled that.

"We hit it off and in 2008, a lot of times when he came into New York, he would hit me up and we got to know each other. Somewhere in that year, Mark and [his sister] Randi emailed me and they're like, 'Our parents are selling a bunch of Facebook stock. Do you want to buy in?'

"I said 'Yep.' That was life-changing."

Vaynerchuk remembered that he went into the dinner thinking "He's a tech kid and an engineer and a Harvard kid," and left thinking "'F---, this kid absolutely gets human behaviors.' That's when I knew that he was going to win, because I'm like, 'Wow, he's got both.'"

Vaynerchuk had always prided himself on his emotional intelligence — "I'm not the smartest. I just know what people are going to do" — and was surprised to find that Zuckerberg had similar traits on top of technical know-how. "He knows how to build it," Vaynerchuk told Shontell. "I can't build stuff. I'm not an engineer. That's not what I'm in to, but I'm like, 'He understands what I understand.' That was it. I was just bought into him from day one. He's super smart."

He continued:

"We're a funny match in the 10 or 15 times we've interacted because I only want to talk and he only wants to listen. That's why he'll probably end up with a hell of a lot more money and be successful, but he's extremely bright. I like him a lot. I think he's kind, but most of all he just understands people.

"That's weird because people look at him as introverted and quirky and all that but I don't see it and I never saw it. Obviously, he's more media trained and grown into himself. I can't speak to how he rolls now because I haven't spent time with him but I can definitely tell you there was no confusion from those initial meetings for me, and I mean none."

Listen to the full podcast interview: