tedster - 10:28 pm on Oct 11, 2010 (gmt 0)
You think I have some special hotline to Mountain View? Sorry to disappoint, Eric Schmidt is not my BFF ;)
I don't think there's any technical mystery about the <base> tag - it's very cut and dried. In addition, it only comes into play if you use the ../ style of linking.
The question of what is going with Google in your case is the mystery. But from this thread, I don't think it's the <base> tag. Also, realize that Google will intentionally experiment with oddly formed URLs, just to see how your server handles it. If your server says 404, then no problem.
If I were you I would put the <base> tag explanation aside and look at the problem with fresh eyes - once more again from the top.