Lars Boilesen, who took over as CEO from von Tetzchner early last year, will continue to lead the company. Since Boilesen took over, von Tetzchner had been working at Opera full time as a strategic adviser.

In an the move. But in a , he hinted at some disagreements.

"It has become clear that The Board, Management and I do not share the same values and we do not have the same opinions on how to keep evolving Opera," von Tetzchner wrote in the letter. "I feel the Board and Management is more quarterly focused than me. I have always worked to build the company for the future."

Von Tetzchner founded Opera in 1995 after he began developing a Web browser while working for Telenor, the Norwegian company that operates telecom networks worldwide. Opera became an alternative to Internet Explorer and other browsers but set itself apart in the mobile market.

Its Opera Mini service works in conjunction with back-end servers that compress websites, loading sites faster and cheaper for end users. It is widely used globally, particularly in regions that don't have high-speed mobile networks and where people don't use smartphones.