RE: [whatwg] notes on current HTML5 draft

One thing XHTML(2) does not provide is resilience to invalid code, which is
very important for sites featuring third-party content like advertisements,
or user-generated content like blogs.  Script-only add-ons like database
access and Web sockets in HTML5 are a big advantage for Web applications as
well.
I would not consider an exhaustive list of serialization issues in various
modes appropriate for the specification itself; this is covered in the FAQ
and it is a straightforward conclusion from the features and limitations of
the media involved (which are specified).
Best regards,
Chris