I had heard that Portus had about 800 attendees and Terminus had 1500. I attended both, and the latter did seem larger, but it is really impossible to judge, as everyone is not in one place at the same time, even for the costume balls. That was an unusual summer, as there were large conferences in both July and August. I have no idea what the attendance was for any other HP conference.
If you really want a comparison, the AARP conferences usually get around 25,000.....and there'll be one in Orlando this coming October.
