Am I wrong to think it's ok to charge a fee for on-line talks? It takes me hours to prepare my presentations, and I'm exhausted after delivering them. How is it that some organisations charge a fee for people to attend talks, but don't expect to pay the people who present them?

If it's free to those who sign up, or a fundraiser, I can understand being asked to waive the fee. But I have rent to pay, and don't have the luxury to be able to work for nothing. And speaking IS my work.

Apologies for the rant, but I genuinely don't understand how this works!