Ampersands in #+AUTHOR: declarations are not correctly escaped by Org-mode.
To reproduce, export:
#+AUTHOR: a & b
You'll find the line
<meta name="author" content="a & b"/>
in the output, but it should be
<meta name="author" content="a & b"/>
The same problem occurs with other special characters in author declarations, and also in #+DATE: declarations.
This is breaking the "XHTML 1.0 Strict" claim.
- Pavel Panchekha