What are the general feelings and experience with the different agreements on these sites? Which ones offer the most protection to the sellers and which one offers the most protection to the buyers? Where could these sites create a new model for licensing and terms of use that is better and clearer for everyone involved?

i've done a little writing about this on my blog and am very interested in hearing anyones opinion on the topic. cheers.

Cutcaster - A Creative Exchange: A New Royalty Free License

not meant to be a shameless blog promo ; - )