Betty joined Earthlink in 1996, and was elevated to CEO in May of that year. He served in that position until November, when cancer forced him to take a medical leave of absence. Interim CEO Mike Lunsford, who formerly served as Vice President of voice and access at Earthlink, will remain in that position, Earthlink said.

"We are greatly saddened by today's news," said Robert M. Kavner, chairman of EarthLink's Board of Directors in a statement. "Garry was instrumental in building EarthLink into the company it is today. He leaves behind a tremendous record of achievement and an accomplished management team committed to pursuing his strategic vision."

Earthlink paid tribute to Mr. Betty on the company homepage with a picture of him displayed prominently, and the message "We have lost a trusted leader and a true friend." The company also posted a link to "social website" portal Ning.com, where a page honoring Mr. Betty . As of Wednesday morning, about 37 people had joined the social networking tribute site, which featured pictures of Mr. Betty and messages of sympathy.

Before joining EarthLink, Betty served as chief executive of Digital Communications Associates, Inc. (DCA), where he was the youngest such head of a New York Stock Exchange listed company, Earthlink said in a statement.

After falling hard following the collapse of the dot-com bubble, Earthlink has recovered in recent years, but is still struggling to maintain profitability.