Donncha - We want to use a mobile theme but from what I can tell is that in order to do that we have to forgo caching for mobile users. Mobile is growing by leaps and bounds and I've read stories of people who had a mobile WP theme and had to disable the cache bypass during heavy loads in order to keep their servers up and running (i.e. there were enough mobile users out there to kill the server). It would be nice to have a mobile theme with a caching system.
A simple solution for WP Super Cache could be to save a special cached version for mobile page views:
Or something similar. If you separate each browser type into simple (WAP) vs. webkit, something like this could be used:
Then the rewrite rules for mobile sites could point at the correct cached files instead of simply bypassing the cache. All other browsers would get default cached files:
That should be pretty clear. But let me know if something above doesn't make sense.