Hi Dennis,
I think there is quite some room for action inbetween "accepting" and "vote with your feet". Protests can have large effects and may be the only option when you actually do not have the choice to "vote with your feet".
Ebay does have a quasi monopole on online-auctions! Thats what put their actions in a different light as if they were in real competition with other companies. I wonder if their efforts to motivate vendors to use fixed prices does have to do with fears about anti-trust activities? It allows them to point to Amazon as competitor...
cheers
Martin
Martin