As part of this, ACM has changed its copyright policies. As an author, you have a special stake in this. You are the source of worthwhile information that must be easy to locate and must not be lost in the junk so readily available in the Internet. It now makes sense to send these to editors for review and publishers for printing. That would speed review and reduce errors in typesetting.
Authors circulate preprints of their papers in their communities for comments.
This improves the quality and catches errors early. It also disseminates new ideas among active researchers much faster than is possible in print. Authors now find that they can send copies of their works to interested parties much faster electronically than through printed media. Authors are beginning to mount collections of their personal works on servers. These collections are part of their professional identities and simplify the task of others who want to locate an author's past work.