What happened to his website, drkoop.com?
It's now healthcentral.com. According to Wikipedia, there'd been some problems mixing paid endorsements with what was supposed to be objective information and the site went bankrupt in 2001 (when a lot of Internet start-ups did).
The interesting thing for me is that he was still well known and current in 1997 when he started the site, and today he's a figure from the distant past. I guess that's what happens when you get old.
Still, according to Wikipedia he was a widower who remarried at 94, so he must not have been totally inactive these last few years.