SEO: how to handle the redirect page to mobile website when there is no equivalent

Question

We have our website as site.com, and the mobile version at m.site.com

When the user arrives, we detect the mobile from the user agent and redirects to the corresponding page there; for exemple from

site.com/some/stuff

to

m.site.com/some/stuff

My problem here is that not every article we have is published on the mobile version and I'm not sure how I should be handling cases where there is no correspondance (/some/stuff doesn't exists on the mobile version).

Should I be:

1. Redirect to the url on mobile version, which then 404 (lots of 404 ? doesn't seem right)
2. Redirect to the url on mobile version, which then 301 to mobile home (no 404 pages on the mobile version ? doesn't seem right)
3. Redirect the url that doesn't exist on mobile to the mobile home, and keep the correspondance for those that exists (lots of page redirected to mobile home for google mobile ...)
4. Not redirect if there is no correspondance (mobile gets sent the full website ? ...)

None of those solutions seems good to me, so how do you guys handle it ? What should I be doing to avoid crippling the seo ranking of our website ?

Thanks

Answer 1

If possible, I would suggest changing your set-up so that all articles on the regular site are accessible via the mobile site. I don't know what your current process is but it sounds like you need to manually add articles to the mobile site. If you can automate that process then you can make this question essentially moot.

A second option would be to not have a separate mobile site but a mobile stylesheet instead, which hides all the fluff and just shows the basic content, formatted for devices. This way you don't even need to detect mobiles yourself.

Otherwise, I would suggest redirecting if an article is available, and not redirecting if no equivalent mobile page is available. The only problem here is what happens when the user is on the mobile site and they want an article that's on the main site but not the mobile site? I would really look at doing one of the first two options above.