Well, if it's any indication of the veracity of Chris Li's theory, E-Budo has been down for a long time, and I wonder whether it's down for the count. Before it vanished, that site had an inactive membership of over 15,000 but only a tiny membership of active posters. Over the years, the attrition just kept up with people simply not coming back.
Looking at some of the other once-popular martial arts-themed websites, participation is sluggish.
Martial arts is a relatively small and specialized interest, with an even smaller population interested enough in the subject to want to yak about it online. The number of martial artists worldwide who particiapte on an English-language site is likely smaller still. Maybe there just aren't enough of them to sustain sites with fresh material and conversations forever. Like a marriage, keeping a web forum lively and fresh takes a lot of work and creativity. Maybe there just isn't enough of anything "new" to do that. IP/aiki may be the last frontier of controversy that keeps some level of "conversation" going.
But I don't think that the Internet overall is on the way out. It is still a great way to share a sense of "community" that individual texting can't achieve. There are plenty of online forums that attract thousands of participants who share a similar interest. For example, check out "Backyard Chickens": http://www.backyardchickens.com/f/
On any given day, that site has over 1,000 people yakking about their pet chickens, ducks, etc. and swapping egg recipes and what-have-you. It's a huge community, with thousands of active participants. No one cares if the same topic is brought up again and again, because there are so many people there that someone will be happy to chime in with advice. The members come from all walks of life and have many other interests besides pet livestock and backyard poultry, so there is constant chit-chat on any manner of subjects. There are no specific agendas.
Forums like that are global substitutes for the old general store or other social gathering spot where a housewife, retiree, young mother, veterinarian on his/her day off, or 4-H kid can hang out. The one thing they have in common that brought them there is chickens, but they are open to lots of other kinds of discussion.
But maybe martial arts forums are too specialized in both subject matter and participant type to sustain that kind of communality. Maybe by nature we're all just too introverted.
P.S. Oh lordy, Chris, I remember that incident with the "well-known Aikido teacher" (and well-liked!)...he wrote about it as a cautionary tale. I joined the Aikido-L listserv (and Jujutsu-L) in 1995. Does anyone here still remember listserves? They actually still exist. A couple of years ago I found out that Aikido-L was revived by a few folks, and also Jujutsu-L was never de-activated. It just lives in the ethers, waiting for someone to post. Kind of sad, like the space-ship greenhouse in Silent Running