One of Silicon Valley's biggest stars, Mr Marc Andreessen, has agreed to become chief technology officer of America Online if the company's proposed merger with Netscape goes through, sources close to the companies said on Monday.

At many companies, the job of chief technology officer means the top computer whiz. But Mr Andreessen's broad interests and energy are likely to give him roles in many aspects of AOL's operation as it tries to become a stronger force in online commerce, industry watchers said.

As a University of Illinois computer sciences student, Mr Andreessen helped create the first practical "browser" for simplifying use of the Internet. He went on to co-found Netscape and was its prime strategist. Now 27, Mr Andreessen is revered as the geek kid who could - and did - succeed in the business world.