His marketing prowess and knack of connecting with the mass market has made America Online the world's largest provider of online services with more than 20m subscribers worldwide.

At the same time, his lack of technology savvy has sometimes put him at odds with some of the early webheads who pioneered the internet.

The quietly spoken father-of-three started his career in the marketing department of Procter & Gamble, which controls the world's leading consumer brands. It was while he was in charge of developing new pizzas for Pizza Hut in the early 1980s that he first came across an online information source.

He was said to have recognised the possibilities of the new technology while balking at its then "user unfriendliness". AOL was born in 1985 out of the embers of a company which ran an online service for users of Atari computer games. It became AOL in 1989 after launching a nationwide service for the first time. But it was 1997's takeover of Netscape which changed the company and Case's reputation.

The takeover of the browser group which had first threatened Microsoft was a coup for Case, who had been appointed chief executive in 1993.

John Sidgmore, chief executive of UUNet Worldcom, who has known the Honolulu-born Case for five years, said after the deal that he had become "the premier chief executive in the internet space". While other internet businessmen claim that Case is too interested in mass marketing for the industry's good, he has long claimed that the new means of spreading information should be available to all.

A former college rock singer, he lists music and sports sites on his own home page but claims that reading political science and social history are his chief interests in the latest edition of Who's Who in Finance and Industry.

The 41-year-old denied that he would be keen to look for other challenges yesterday.

He told interviewers that he would like to spend the next 10 or 20 years as chairman of AOL Time Warner.