If you transfer copyright at all, you typically only transfer it to the ACM, not Springer. Springer is just a contractor running a website and occasionally printing up phone books of papers that no one reads, and USB drives of PDFs people use for the week of the conference.<p>See <a href="http:&#x2F;&#x2F;www.acm.org&#x2F;publications&#x2F;policies&#x2F;copyright_policy" rel="nofollow">http:&#x2F;&#x2F;www.acm.org&#x2F;publications&#x2F;policies&#x2F;copyright_policy</a>