Dear Humberto

Very interesting responses, thanks – my comments:

A) "Most likely just a difference in the different collections of “things” to search in."

Surely incorrect.  I began publishing to the web specifically via Academia – long since - following staffers at the British Museum – my impression is something similar happen very widely, and that many more numismatic papers go to Academia.edu

B)  "Numismatic is not an economic subject and Academia has papers from different areas, I think"

This rather promotes the attitude: “I already know the answers, do not bother me with the facts”

C) "SSRN and RePEc do not offer full text search. SSRN could, as they have the full texts. RePEc only links to them."

In reality the full search facility might not be all that useful in practice, EG Academia.edu lists as users an astonishing number of different people with names of the form “David Ricardo X X”

On a perhaps parallel matter – when as a private citizen I opted to write a book back in the 1990’s I wrote to a single official national body who immediately allotted 20 ISBN’s for my personal use, for a one time trivial fee.   The default position with DOI’s for web pages seems to be that allocation is sub-contracted to “sponsors” who register to pay $200+ annually. (I notice CERN is already involved in a work around)

I judge the default reality rather hiding behind these words resembles what Adam Smith called “the Mercantile system”. Perhaps others disagree?

Robert Tye, York, UK