Ebay recently changed their feedback policies so that sellers can not place negative feedback on buyers. I assume thus you only get a choice of positive and neutral. This will cripple the ebay feedback system and really limit is effectivity. In the long term I am absolutely certain its a step that will be reversed. I want to suggest we quicken this reversal with a method that hurts them the most and sellers the least.
In response alot of sellers have been trying to stir up a boycott of ebay. The problem with this is that the sellers need ebay too much. Thus a frontal attack of this sort will not work.
If ebay sellers want to effect a boycott without hurting themselves there is a method. Boycott placing positive feedback on buyers. This will stop their flow of new users. If a new user has (0) next to his name I will often decline to sell or ship to them. This is especially true if its a buyer outside of the USA.
With this method you will not only be able to make your sales but it will hit ebay where it hurts. In the user growth numbers.