Having been away from active FPGA development for
a couple of years, I
was surprised to discover the sorry state of Xilinx's documentation.
Perhaps it has always been this way...

Xilinx Application Notes -- I have found two application notes on the
Chinese Xilinx site that do not appear on the main Xilinx web site
(XAPPs 730 and 934).  Has Xilinx pulled them?

Webpack Supported Devices -- A simple Google search for "Xilinx
webpack", performed to find the list of supported devices, returns out-
of-date information that is not appropriately marked.  Namely the
second hit (http://www.xilinx.com/ise/logic_design_prod/
webpack_faq.htm) is an FAQ for the 8.2 version of the tools.

Documentation Search Engine -- Though the main Xilinx site is up, I
cannot get their documentation search engine (http://www.xilinx.com/
support/documentation/index.htm) to respond.