Back in the good old days before the internet, scholarly journal publishers would mail printed calls for papers to university departments around the world, and these departments in turn would post them on bulletin boards in or near the department offices.
In those days, there were few or no predatory publishers, so pretty much every call for papers was for a legitimate journal — no vetting was required.
This has all changed with the internet. Now we are bombarded with calls for papers, usually via spam email, and many of them are from predatory publishers. Many of these are forwarded on to scholarly email lists — often blindly — without being vetted for quality.
Some websites try to be helpful by posting calls for papers. One example is the American publication and website called Inside Higher Ed. This journal appears not to screen the CFPs it receives and uploads them to its website here. However, at the time of this writing, the website lists multiple calls for papers for OMICS Group journals, a publisher I have identified as predatory. Referring scholars to OMICS’ journals is not helping but rather harming them, I think.
Times have changed, and I think that due to the existence of predatory publishers and predatory journals, it is negligent to forward calls for papers without eliminating the predatory ones.
An example of a site that pays careful attention to the quality of the publishers behind the calls for papers is ResearchRaven™, which lists calls for papers in the health sciences, medical humanities and the health-related social sciences. Their calls for papers for publications page (they also have a call for papers for conferences http://www.researchraven.com/calls-for-papers-conferences-and-meetings.aspx) is carefully and professionally screened for quality and stands as an exemplary model of how calls for papers should be re-distributed.
One final note about grammar: in standard English it is ungrammatical to say “Call for paper” when issuing an invitation for scholarly manuscripts. The correct phrase is “Call for papers.” In the native English speaker’s mind, “Call for paper” means the same as “Hey, bring me some paper.”