We note that one of the papers presented in the workshop is not included in the proceedings. This paper, "Functor is to Lens as Applicative is to Biplate: Introducing Multiplate" by Russell O'Connor, is accessible as arXiv:1103.2841v2 [cs.PL].Russell gives his account but he focuses on ArXiv instead of the public domain aspect. In the STOC CFP we encourage putting your submissions on ArXiv and similar sites. The issue that worried ACM was the loss of rights. ACM could have published the paper, it was in the public domain, but it wouldn't have control of that publication and didn't want to set precedent. Scott Delman of the ACM responded here.
An academic paper you write has little direct value to you (the paper itself not the Intellectual Property within). No one is likely to give you any money for that paper. But your paper does have financial value as part of a collection in a journal or conference proceedings. Commercial and non-profit publishers know how to collect on this value. You might complain that this puts your paper behind a firewall but all the major publishers in CS allow you to post earlier drafts on your homepage and archive sites. As long as you make that effort, people will have access to your papers.
It does take some money (or considerable person hours) to maintain even an electronic journal or conference proceedings. But publishers get more value than that. For the ACM, the DL revenue is a major source of funding for ACM activities and those of the SIGs.
Of course you should never trust the opinion of someone who has a financial interest in a position and as SIGACT chair, we certainly make use of the DL revenue. We are hoarding some in case the DL revenue shrinks in the future.
It seems a shame to leave the monetary value of our papers on the table but also that value shouldn't be exploited. Big discussions will continue on the publications issue, at ACM and other publishers and at all levels of the CS community. There will be a Dagstuhl workshop focused on this topic in the fall. Figuring out the right model for publications will not be an easy one.
My biggest fear is that lack of a plan will lead to a degradation in the quality of our publications and then everyone loses.