"The spirit of this provision of the law was to allow limited distribution and sharing of information not wide-spread distribution as would be done if a copyrighted article from the 'magazine' was posted by a member on a forum available to several hundred thousand members."

Copyright Law - the governing law - does not stipulate any given quantity and, therefore, I presume you are incorrect. The only cases I have seen involved copying and using a substantial portion of the publication - of which, one tutorial would not be considered substantial.

If it is a learning/teaching session on a site that may have "several hundred thousand [listed, not active] members" which - at any given point in time - less than 2,000 (1%) are online, and an even smaller fraction visit the forums in general, with an even smaller fraction participating in that particular thread, I am sure that you can see that the "several hundred thousand members" becomes a moot - if even existent - point.

The "numbers game" is always played here and hardly factors into anything from a practical standpoint. Just think of how many news/review sites there are, their audience, and you will see that the scenario you presented is extremely far-fetched.

"Once a contract is agreed to, even the author of the article would would be hard pressed to show his publishing the article on such a forum constituted fair use..."

Not so. The author-publisher relationship does not preclude nor interfere with the subcriber-publisher relationship. The Federal (remember that word, it is important) rights of Fair Use apply to everyone (that word is important, too).

More likely, R'osity will have a hard time proving it was not Fair Use; since the whole purpose of a tutorial is to tutor (ie, teach) a subject. The most R'osity could hope for is using such a stipulation against future publication (ie, if you make your material available, we will not publish your tutorials again). Here again, an author would be daft to accept such terms and R'osity would be jeopardizing the content they rely upon for the Magazine to be successful if they did press the issue; so R'osity would lose either way.