On this forum, we often discuss differences between different implementations of SQL, or discuss picky questions about tiny details of SQL and how they 'should' work. Typical examples are those concerning what NULL means when used in various contexts.
We can rarely answer these questions because, as some of you know, the SQL standard is declared by the ISO, and to get a copy of what they think 'SQL' means, you have to pay a lot of money. I think last time I added it all up it was somewhere around US$11,000 for copies of all documents related to SQL. And the standard changes every four to six years and the change notes are not free, so that sum might last just four years.
The ISO earns almost as much from selling copies of the standards as it does from membership fees. It has been categorising more of its publications as chargeable documents without consulting ISO members or the authors of those documents.
A number of high-profile technical writers have called on the ISO to make all their standards publicly available for free. You can find their reasons and names here (eight page document)