Technically, 30-50 or so.
In reality, I haven’t been to a Dopefest in years and 90% of those I’ve met are probably no longer 'Dopers.
I think that many more Dopers would have a chance to meet other Dopers if we had a way to identify ourselves to each other, say like a Straight Dope T-shirt or something like that.
That might help, in between Dopefests.
Well, I’m technically still here. I just don’t really post.
Let’s see…
Santo Rugger
Astroboy14
scout1222
Encinitas
Taber
Am I forgetting anyone from the San Diego mini-Dopefest at that Korean BBQ place?
Either way, I’ll be meeting a bunch more Dopers at Roscoe’s this Saturday!
Oh, so I’m the only one that screams “Gotcha Ya!” when entering a crowded restaurant? 
I’ve met four Dopers
tdn
bbs2k
Robot Arm
Autolycus
when these gentlemen were all in the greater Boston area.
I have met one, WordMan. A couple of years ago his band happened to have a gig in New York while I was visiting my sister-in-law in New Jersey. My wife and I enjoyed a good meal, a great band, and an online friendship got even better. A worthwhile trip.