I am developing a site with a mobile version and am trying to figure the appropriate way to manage the URLs for search engines. So far I've considered:

1. Having a mobile site with rel="canonical" links to the regular site.
2. Putting both the mobile site and full site on one URL, and doing user agent sniffing.
3. Another opinion:

Spencer: "If you have a mobile site at a separate location or URL, you should 301 redirect each and every mobile page to its corresponding page on your main website. Employ user agent detection so that the mobile optimized version is served up if someone's coming in from a hand-held.

• http://developer.practicalecommerce.com/articles/1722-Mobile-site-Development-Best-Practices-for-SEO-Usability

Both 2 and 3 make it hard for a user who wants to switch to the full site or mobile site manually, but I'm not sure 1 is the best alternative.

What's the best way to write URLs for a mobile site?

I am developing a site with a mobile version and am trying to figure the appropriate way to manage the URLs for search engines. So far I've considered:

1. Having a separate mobile site (m.example.com) with rel="canonical" links to the regular site.
2. Putting both the mobile site and full site on one URL (example.com), and doing user agent sniffing.
3. Another opinion:

Spencer: "If you have a mobile site at a separate location or URL, you should 301 redirect each and every mobile page to its corresponding page on your main website. Employ user agent detection so that the mobile optimized version is served up if someone's coming in from a hand-held.

• http://developer.practicalecommerce.com/articles/1722-Mobile-site-Development-Best-Practices-for-SEO-Usability

Both 2 and 3 make it hard for a user who wants to switch to the full site or mobile site manually, but I'm not sure 1 is the best alternative.

What's the best way to write URLs for a mobile site?