After reading Scoble's post, I believe it may be a good idea to promote something like a "Pay-per-speech" disclosure.
It seems that some times sponsors may press conf organizers to get as much exposition as possible and even may want to influence the program and the speakers.
Also, it is an embarassing situation to attend to a conference and listen to a speaker who is off topic or just doing pure advertising, on behalf of the sponsor.
I don't have a problem listening to an interesting speech by a representative of a sponsor, specially when this situation is clearly identifiy. The audience will know and will decide to attend or not.
I think is an ethic way to do it and add more credibility to lots of confs that have to deal with that issue.
Tags: PR, RRPP, Public Relations, Relaciones Públicas, Comunicación Corporativa, Corporate Communications