I think the real question is whether it's important for your Web site to be mobile-friendly. If the answer is "yes," you need to think about how and whether AdSense will work with mobile; if it's "no," then you can scratch that issue from your "to do" list.

This is a very good question. I would love to know the stats but I would guess that even less people click on ads when using a mobile than they do whan surfing from a regular laptop or pc.

I believe it is very important to make your site mobile but I am also concerned about having to find a new ad revenue source that will complement it.

added

In fact the mobile forum at ww is one of the quietest here. Quite amazing when you consider it is tomorrow's technology already being used today.

[webmasterworld.com...]

I use my mobile to surf more each day. But my habits when surfing are very different than when I am on a bigger screen.

[edited by: Visit_Thailand at 8:13 am (utc) on Nov. 13, 2008]

First generation phones didn't support Javascript so Adsense didn't work on those devices (unless you selectively ran Adsense for Mobile).
Newer mobile devices such as the iPhone do run Javascript. If that trend continues there will be no need to detect and run Adsense for Mobile.
I haven't tried the iPhone yet so I too am wondering if there is any special adaptions we should make for publishing Adsense.
For instance, is the phone more often held in portrait or landscape orientation when surfing the web? Do you zoom out to the full width of the page then zoom in on sections that catch your eye?
I'm going have to get an ipod Touch (maybe for Christmas) and try it myself.

With the mobile revolution slowly creeping in, us adsense-adepts would do well to educate ourselves on optimizing for tiny screens. One problem here is the size of the ad units; a 336x280 could easily eat away at least half of the user's screen. Is there a balance to be found in content / ad when it comes to smaller resolutions? Maybe the answer is on selectively serving ads based on user agent, but we all know how unreliable that can be.
Have you thought of a strategy yet? Mobile is coming (in fact, it's already there but not on the scale it will likely evolve to) and we'd better be ready. Would love to see some thoughts on this.

I just tested on my new Sony Ericsson w910i my web site.
It's a joke! German special characters not shown correctly
  even non breaking space not showing correctly

Screen size 240x320.

I just redesigned my site for 1024 pixel width minimum screen size. Smaller resolutions are less than 3%

I think more on a boom of netbooks with 1024x600 as minimum screen resolution.

For the time being mobile sites have to be developed in WAP 1.x or WAP 2.x standard without tables etc. You can run your site via the [ready.mobi...] validator to get an idea how the website should work.

Another could option is to use a php script that detects many different mobile devices, so if a phone that supports javascript you can serve a real adsense banner but if it is a mobile device you can deliver and advertisement from Mobile Adsense. I have been doing it for the past 2 years and it works great.

I'd guess that display ads of one type or another would be a better fit for mobile devices than AdSense ads are, for the reason that Visit Thailand suggests--i.e., user behavior.

The holy grail for mobile advertising is a system that uses GPS to deliver display ads for businesses near the user's location ("Thirsty? Say 'Gimme' to save 50 cents on a smoothie at Widgets, 34th & Main.") That's a far cry from the kinds of ads that AdSense delivers (at least for now).

Leonard0, I've got an IPod Touch and my site looks normal on it. AdSense displays just like on a regular PC. What is interesting, to me, is that you can zoom in to a div by tapping the screen where you want to zoom. That is great for readers, but then they don't see the ads if they just scroll through that div.

I'm thinking that an inline (in content) placement, rather than the right column I use now, would increase the chance for mobile surfers to see the ads.