It is and it isn't. ACM provides a clause which lets you upload pre-print versions of your work. In Computer Science, where its almost guaranteed the academic

It is and it isn't. ACM provides a clause which lets you upload pre-print versions of your work. In Computer Science, where its almost guaranteed the academic did the typesetting anyway, the pre-print and the actual camera-ready version is identical. I was working for a university Computer Science department, and trying to build a paper repository. The library, which took copyright very seriously, was adamant that we couldn't store copies of the papers, and that the academics couldn't either on their own sites. The academics were very angry at this, and I got in the middle of a pretty vicious crossfire. It was the worst time I ever had at that job. ACM doesn't police it. They don't want people setting up rival repositories, that's all. However, Citeseer seems to be skating on very thin ice, and Google Scholar has made it much easier to find those "pre-prints". I see ACM not as a professional organization but a conference organizer/authenticator. Their magazine is also pretty good too.