edik

If FacadeX is active, the public WordPress sites are sent with the xhtml mime type. The internal sites like the administration panel and the login screen, which have many xhtml syntax errors, are still sent with the standard mime type.
You must ensure that your public sites have valid XHTML, otherwise you will get parsing errors in your browser.

FacadeX

Sends public sites with the XHTML mime type. The internal sites, which have many XHTML errors, are still sent with the HTML mime type.

dberube

MoFuse (http://www.mofuse.com) is a service that allows bloggers to easily create a mobile-friendly version of their blog for free.
This plugin allows you to automatically detect and redirect your mobile visitors to the mobile-friendly version of your blog.

MoFuse WordPress Plugin

Requires at least 2.0.2 Test up to: 2.7.1 Stable tag: 2.7.1 This plugin works with a MoFuse account.  This plugin will automatically detect and redir …

FacadeX vs MoFuse WordPress Plugin