Larry wrote: [An impassioned and earnest defense of linkbacks]
I agree wholeheartedly.
The only thing is that the GFDL already requires linkbacks in pretty much every situation.
We don't need to add an invariant section unless we want to determine the look-and-feel of the linkback.
What we need to do, at a minimum, is follow the nuances of the GFDL and comply with it, and give our recommendations on how we believe (without giving official legal advice) you (Joe Q. Other) can use Wikipedia content in compliance.
We should frame it as "All you have to do to use our stuff is follow the GFDL. If you do these things [list] we (Wikipedia/Bomis/etc.) will consider that you are successfully following the GFDL. But the list is only a set of recommendations and is not legal advice."
Then we can say "This HTML table is the recommended way to link back to Wikipedia. If you put it on your site, you will not only be complying with the GFDL but also helping grow Wikipedia."
etc. etc.
But first steps is actually understanding the GFDL, which requires a close analysis. I recommend doing it.
On another note, I think it's bad policy to leave the HTML table page up as the official policy while a) it's being discussed, and b) the Wikipedia principals have unofficially distanced themselves from the requirement.