The big problem for me is not that there is nothing to be gained from speaking for free, but that in some cases money is changing hands, and some people (even ignoring caterers, stagehands, etc.) are getting paid and making something off the event.

And if that's the case then why not pay those who provide the content?

It's interesting to see the amount of support here for doing a TED talk for free when it seems to me most people on HN take a different stance when it comes to doing free design work. In those cases the arguments about getting exposure seem to carry much less weight.

People should be careful not to spite themselves, but at the same time we should not let ourselves be taken advantage of.

Kind of short sighted. Sometimes you give talks in order to get more talks. From experience, that's how these things work. All of my paid (not that there were too many) speaking engagements came in some way or another as a result of speaking at a nice venue for free.

Also, I personally enjoy going on stage very much.

Indeed TED events are costly, but TEDx are not, and there are hundreds of them around the world every year. No reason TED global should sponsor them.

Finally, if you're really passionate about something, an 18 minute talk is something you can give away for humanity's sake.

I think that you are right about this paying stuff. If you have anything better to serve, then you have a right to get paid for it. But, I also support this fact that TED is a global exposure stuff for any speaker and if you get any chance here, then it means that you have something special inside you which makes you a distinct personality. So, go and talk again about the offer. It is worthy to take.

Market price is set by the supply and demand - I wouldn't be surprised if there are actually more qualified people who want to speak at TED for the current price of $0 than the spots for these speakers; so a 'fair market price' might actually involve you paying them...

Not all speakers do TED(x) for the sake of congratulations or personal exposure. The best talks are the ones where the message is the most important thing. For someone caring deeply about their subject, that's usually the greatest reward.

I've heard of high profile TEDx speakers getting $$$$$$ for presenting. Is there actually a rule somewhere about NOT paying speakers?