Amazon S3 (Simple Storage Service) is an online storage web service offered by Amazon Web Services. Amazon S3 provides unlimited storage through a simple web services interface. Amazon launched S3, its first publicly-available web service, in the United States in March 2006[1] and in Europe in November 2007.[2] Since its inception, Amazon has charged end users US$0.15 per gigabyte-month, with additional charges for bandwidth used in sending and receiving data, and a per-request (get or put) charge.[3] As of November 1, 2008, pricing moved to tiers where end users storing more than 50 terabytes receive discounted pricing.

Is that the basis of the conflict?
Is it that Renderosity will derive an economic benefit from storing the files here while the Free Stuff authors have to pay to have redundant files stored at their sites?