Ray Saintonge wrote:
I've sometimes wondered about the purposes of the ISBN links in articles, especially when they appear without the author or title of the publication being mentioned. For me links to books are more in the nature of bibliography. Wikipedia is not in the business of book promotion, and even less in the business of promoting these books as produced by specific publishers. Your experience with the Goldsmith book is highly illustrative.
As a point of history, it just happened that the original Usemod software had this feature, for whatever reason, and so people started using it. I'm not sure we would have done it in that way had we started from scratch.
On the other hand, although wikipedia is not in the business of book promotion, I think it's very useful to have an easy way to auto-link book titles to places where people can obtain the book, either through purchase or interlibrary loan, or whatever.
Often, I might be researching some topic and of course I turn to wikipedia first. Having learned about such-and-such author, I now want to buy a book. It's nice to be able to just click and go.
I certainly agree that we should have a diversity of sources, so that we don't appear to be endorsing any specific merchant.