The link to regarding the utf-7 security risk doesn't work any more. See http://blog.php-security.org/archives/38-Wikipedia-UTF-7-XSSCross-Site-Scripting-Hole-Plugged.html instead.[January 2012]
Now there is! It's called <main>. Use it once per page (like ARIA's role="main" to surround your main content, eg don't include header, footer, main nav etc.) The spec says:
The main content area of a document includes content that is unique to that document and excludes content that is repeated across a set of documents such as site navigation links, copyright information, site logos and banners and search forms (unless the document or applications main function is that of a search form) …
Authors are advised to use ARIA role="main" attribute on the main element until user agents implement the required role mapping.