Been thinking about it too.
- "Mobile device" is not clearly defined as a pure standard with X or Z fixed properties, so we have armbooks, cell phones and multimedia players with internet access all with diff screen size and ways to access the web (pure browser, proxy or mobile view).
- Making our sites accessible is not a problem as despite how they look, people still see our sites with what they have. The problem is to make them look pretty and still earn money the usual way, in this case, Adsense.
Access to the sites can be solved via CSS for mobile devices or scripts detecting the agent, browser and redirecting to an specific version of the site. I see this as a faster way to adapt our sites to mobile devices without doubling our mainteinance taks.
The problem is #1. Been testing with cell phones and diff OS and webbrowser software on my armbook. Depending on the browser there is a different "mobile view" created by the browser itself (thats variable A.) Some browsers variants of mobile view, so there not always ONE mobile view available (that would be A.1). I also found some browsers having "desktop view" where they try to show the webpage as it is on a desktop browser. Anyway it changes the look and possibilities to click the ads on a small screen (variable B). Well, you can still configure the browser to identified itself as whatever you want (IE, FFX, etc).
Most of all, some mobile browsers have some sort of proxy view or "alternate format" such as Opera Mini, where they don't use HTML. Your site is readed on their servers and an alternate version is sent back to your browser.
This last point is what matters to me as the ads are not showing anymore, so there is no way to earn money from those users, even if their screen size is one of the cell phone or even 10" on an armbook. I don't see how to fix this as a lot of the format will be interpreted by the servers so there is still work to do there on what will work and what wont (to still display the ads). I've seen local JS executed but external stripped. I guess:
One solution would be to insert the ads with local JS (still not a guarantee) but images or text ads with redirection scripts would definitely work, but that's extra work. That wouldn't fit the "avoid this" proxies and server content conversion target for removal. A CSS trick would hide and show the options we want to depending the user.
The problem is still Adsense... we can't just create an alternate version of the served ad to be printed that way... (direct link). Modifying the ads is not allowed. In that case I think G has to work on it. Or, we could implement our own alternate AD system.
An alternate system could help. The way I see it, one average site with 3 Ad areas would mean some problem as a lot of mobile devices use gestures and having 3 ads on a small screen could mean invalid clicks. So, I think a mobile site could get away with 2 ads maximum (just my opinion).
I've been thinking on two possible solutions for this in my case.
A. Having my own CMS it is very easy for me to create an alternate version of my sites removing the Adsense tags and inserting some other way to earn money, even direct image or text ads. This way the pages will be serverd as pure html, no extra work required except creating the solution once.
B. Some sort of crawler and conversion tool. Been thinking on creating a script that reads the pages on my website (pure html) and convert them to text only + low res images + link structure. This way I could create a cache of the site for mobile browsers and insert there whatever I want. The difference from B to A would be, this could be installed on every site I use even if they work on a diff CMS. Only the new pages would be added and the redirection would take place via scripts too.
As I mentioned before the problem is to keep using Adsense without breaking the rules (modifing the code) and still serve the ads. I still think G has to work on this or give us some slack.