Google's foray into mobile advertising has predictably fueled further speculation into the possibility of a Google phone, or mobile operating system. "Google is widely believed to be working on some kind of mobile operating system software or perhaps even a mobile phone to ensure its efforts to distribute ads aren't undermined by the owners of proprietary wireless networks and handsets," wrote the Associated Press. Google declined to comment.

Google's AdSense for Mobile comes in two formats: single and double. Google's AdSense publisher terms don't appear to have been updated, so theoretically, mobile publishers could place up to 3 ad units on their content (i.e., up to 6 ads). I wonder whether text ads will have the same sort of success on the mobile web that they have had on the general Internet. Clicking on links often requires more work on the mobile web and screen real estate is so limited that ads might be seen as more invasive.

Also making mobile ad news yesterday was Nokia, who acquired Enpocket, a Boston-based mobile ad provider. Red Herring looks at Nokia's purchase as a reflection of the company's announcement last month to transform itself into a software and services company.