At the start of a session, http://www.OpenYard.com uses the open-source WURFL.xml to recognize if your browser / device is mobile. At that point, we'll choose to load the site in XHTML Basic 1.0 or regular HTML. From a users perspective, I think it's simple for the users to understand and from a performance perspective, the process is quick and easily maintainable.

Here's some questions: Will I be penalized by Google and others for submitting the same URL's to both the Regular Site map AND the mobile site map? For example, will the mobile-bot flag the pages as mobile and will that override their presence in standard search results? Will the pages be seen as 2 pages or 1? Or even maybe a page that constantly changes it's content?

Since the mobile device functionally limits users to what they can achieve or experience on a mobile device, we will render a slightly different, although very similar, page. Does anyone think I should be routing users to a mobile/wap sub domain like other sites do? I feel like sites like Google and Amazon both have the technical ability to achieve what I'm doing but both seem to embrace having separate mobile sites. I have yet to find a site that uses the same URL to load cleanly on my phone and on my browser.

Possibly someone who loads the same url in multiple languages will easily be able to comment.

I've actually done a little testing recently and discovered that I'm not accurately detecting all mobile devices so if you can, please focus less on the literal url and more on the scenario. I think it's interesting, especially as we begin loading the web into many different devices.

Justin,
I think that so far Google and Yahoo have taken the approach that there is no difference between mobile sites and desktop sites. This can be an advantage, but also an issue, in fact, it will be good for your site that all the content available it indexed and can be searched, the problem is that mobile users will get results for their searches that mix up desktop sites that are not meant for mobile (and that Google and Yahoo try to convert on-the-fly) and proper mobile sites. I can also envision a day in which desktop users will get mobile sites mixed in their results.

I work for dotMobi, so maybe I'm not the best person to suggest this, but using a .mobi site seems to be a good way to make sure that search engines and proxies understand that you are really producing mobile content.

If you want to go for a single URL, which is an understandable decision, I suggest that you still try to recognize properly even regular bots and mobile bots so that you will provide the proper content to each. For example the Google mobile bot will flag your content as mobile and give it a slightly higher rank in mobile searches.

Using sitemaps and mobile sitemaps is also a good idea.

Hey Guys – I've actually taken away the functionality of detecting mobile devices. In theory, it made a lot of sense initially but I've thought about a different solution involving sub-domains. There are just so many devices to detect, not to mention other things to detect, such as language..
If anyone is interested in talking about it.. Let me know. But for now, I believe having multiple slightly different URL's is critical for many reasons.

we are currently using handsetdetection.com to manage access to the multiple sites from the one url – are we better not to do this and have them run off m.domainname and pda.domainname etc?

I prefer sites using different sub domains instead of different formats from the same URL.

When I'm browsing from my Nokia mobile with S60WebKit browser or Opera Mini, I mostly want the web pages to look the same as on a ordinary computer with Firefox. Only sometimes like checking real time schedule of buses/metro, one thing I almost only do from the mobile, I prefer the simpler wap/wml or xhtml from a sub domain like m.example.net

Ken, I actually went with the m.domain for the mobile site and the www.domain for the regular html. The reason is, detection is just wayyy more involved than I realized. Not only that but I think it's important to leave yourself open for other sorts of site wide detection, for example, language.

It's always fun and a learning experience to take an idea and follow it through to a conclusion.