I once had a friend who had an interesting idea about her pay when speaking at a conference. In lieu of charging an honorarium for general sessions or keynotes, she envisioned passing an offering plate at the end of her talk and asking people to make a contribution based on how valuable they found her presentation.
While she never actually did it, I'm convinced that the quality of her work would have led to much bigger paydays from the participants than the fee she was charging the sponsoring organization.
Paying for value. It's an idea that seems to be increasingly gaining traction be it artists releasing CDs online and letting you pay whatever you want ... to pay what you can for local theatre performances ... to advertisers paying ad firms based on actual sales changes from the ad campaigns they design as opposed to flat fees regardless of the ultimate results.
Whil I doubt many professional societieis would ever fully embrace this mindset when it comes to member dues or conference registration, I'd sure be curious about what price people would pay to affiliate or attend if they were able to name their own terms. Given the minimal value associated with some memberships and conferences, I'm not really sure just what it is we are paying for or why people continue to do it.