His primary achievement in life was to persuade Yahoo! to buy his broadcast.com business for nearly $6B (which was shut down very soon thereafter).
The same is true of Paul Graham, too (viaweb). Yahoo! made a few lucky people a lot of money, while impoverishing Yahoo! itself.
Preceding that, really, his primary accomplishment was the Russ Hanneman-esque literal "RADIO ON THE INTERNET", which of course what was broadcast.com
I'm just old enough to remember the hype and growth around realnetworks and realplayer in the seattle area too.