What Is Mobile Friendly Site

I have developed and maintaining several websites. These sites meet W3C standards because not only that search engine robots gobble sites that meets certain web standards, I cannot tolerate that sites look different on depending upon a browser. W3C web standards conformed site does not eliminated the issue of uniformity view of sites but it is easier to manage that issue.
Mobile friendly site?
For about year I have been lirking on mobile websites to create mobile friendily site. I used google analytics and have been keeping tab on users browsers. Less than 5% of browsers are of mobile phone or device. But alarming detailed of that was how long users stayed and the bounce rates of mobile browsers. Extremely short stays and high bounce rates. This analytics summary has summoned my search for creating mobile friendly website. I still have uncertain composure of mobile friendly website. I have compiled a basic theme and idea of creating mobile friendly websites. Following are basics of mobile content:
Usable Screen Width
120 pixels, minimum.

Markup Language Support
XHTML Basic 1.1 [XHTML-Basic] delivered with content type application/xhtml+xml.

Character Encoding
UTF-8 [UTF-8].

Image Format Support
JPEG.

GIF 89a.

Maximum Total Page Weight
20 kilobytes.

Colors
256 Colors, minimum.

Style Sheet Support
CSS Level 1 [CSS]. In addition, CSS Level 2 [CSS2]@media rule together with the handheld and all media types (see CSS 2 Media Types).

HTTP
HTTP/1.0 [HTTP1.0] or more recent [HTTP1.1].

Script
No support for client side scripting

In the mean time, I have been reading and browsed through google mobile sites
at http://www.google.com/gwt/n.
I would use google mobile to browse through my sites to get an input of brain storming idea how to modify a site.
Although many mobile devices can already access the Web, actually browsing the Web from a mobile device is often a frustrating experience. Users normally find that their favourite Web sites are not accessible or more difficult to use on their mobile phone compared with their desktop computer. Content authors have difficulties building Web sites that work well on all types and configurations of mobile phones that offer Web access.