Reid Hoffman, the billionaire co-founder of Linkedin, goes way back with Elon Musk. They were both part of the "PayPal Mafia" — a group of important executives at the company, many of whom have gone on to achieve other successes in technology and business.

Hoffman sat down with Adam Bryant for a wide-ranging discussion. Musk came up as a figure generating a lot of headlines these days.

Hoffman called Musk "one of those ... forces of nature" who "tackles problems that most people think are impossible to tackle."

"I think we want more entrepreneurs like Elon," he said.

With regard to his tweeting, Hoffman said, "I tend to have a [reaction of] 'Ok, learn from that. But I'm really glad you're creating these businesses.'" Although he emails with Musk, "Sometimes you need to be silent when you otherwise feel like this is a fight you feel like you should be taking."