Bitcoin‘s meteoric rise is reminiscent of how Skype started out, a former executive at the online phone and messaging service has said.

“We’re seeing this tremendous interest from the rest of the world which is, for normal people, beginning to get terribly interesting,” Michael Jackson, Skype’s former chief operating officer, told CNBC during a phone interview Wednesday.

Jackson said increased interest in the virtual currency — which is now worth more than $15,000 a coin — took him “right back to the beginnings of Skype.”

“We were messing around doing all sorts with the internet and it kind of worked, and all the tools were nerdy and all the nerds used it, and it was great,” the entrepreneur said.

“And then we managed to knock together something that normal people could use, and that was really what created the company. I don’t think we’ve got that in the bitcoin just yet. That’s ahead of us, for sure.”

Jackson is now a partner at venture capital investment firm Mangrove Capital Partners, an early investor in Skype.

He said that bitcoin’s surge is “great” but added that it was difficult to tell what the future holds for the digital currency.

A number of big bank executives have criticized bitcoin due to concerns over speculative investing and a lack of regulation.

Jamie Dimon, chief executive of JPMorgan, has called the cryptocurrency a “fraud” that will eventually “blow up,” while Credit Suisse CEO Tidjane Thiam described it as “the very definition of speculation and the very definition of a bubble.”

Mangrove’s Jackson said that he didn’t believe this to be the case.

“I don’t think it is (a bubble). I think if you look at the economics and the value behind all of this, there’s tremendous upside in it. It’s not a zero-sum game and it’s not necessarily a bubble.”

Experts believe more institutional money will flow into bitcoin as several derivatives exchanges get set to introduce futures contracts for the digital currency.