According to its website:
As the world’s leading provider of science and health information, Elsevier serves more than 30 million scientists, students and health and information professionals worldwide.
The site goes on to claim some 7,000 employees for the company in addition to a “global community of 7,000 journal editors, 70,000 editorial board members, 300,000 reviewers and 600,000 authors.”
The mathematicians’ statement, speaking strictly of their own field (though it is the same elsewhere), explains what that means:
The editorial board of a journal is a group of professional mathematicians. Their editorial work is undertaken as part of their scholarly duties, and so is paid for by their employer, typically a university. Thus, from the publisher’s viewpoint the editors are volunteers. When a paper is submitted to the journal, by an author who is again typically a university-employed mathematician, the editors select the referee or referees for the paper, evaluate the referees’ reports, decide whether or not to accept the submission, and organize the submitted papers into volumes. These are passed on to the publisher, who then undertakes the job of actually publishing them. The publisher supplies some administrative assistance in handling the papers, as well as some copy-editing assistance, which is often quite minor but sometimes more substantial. The referees are again volunteers from the point of view of the publisher: as with editing, refereeing is regarded as part of the service component of a mathematician’s academic work. Authors are not paid by the publishers for their published papers, although they are usually asked to sign over the copyright to the publisher.
In other words, Elsevier (like all of the other publishers of academic journals) is making oodles of money through work paid for by the colleges and universities employing all of those editors, board members, reviewers, and authors. The work is done so that the scholars can achieve re-appointment, tenure, and promotion within university systems. The publishers have taken advantage of this for their own profit, returning almost nothing for what they take to the institutions making their profits possible and sharing little of what they gain with the actual producers of their “products.”
To date, almost 5000 scholars have signed statements through The Cost of Knowledge (I am one) pledging to refrain from editing, refereeing, and/or authoring works for Elsevier.