Google has started limited beta testing on AdSense for mobile with select websites. So far, it appears that the program is limited to those invited by Google. Requirements include that sites are written in either Wireless Markup Language (WML), Extensible Hypertext Markup Language (XHTML) or Compact HTML (CHTML). The program will later be refined from user feedback.

Mobile seems ready to hit its stride and this announcement from Google will certainly add fuel to the fire. "Mobile advertising is a huge opportunity for us starting with the basic premise that there are something like 3 billion or so handsets in the world," said Dilip Venkatachari, director of product management responsible for mobile monetization efforts at Google.