I have costumer who is complaining about massive data traffic on their mobile devices when they enter their website from their cellphones or tablets.
When we made the site in the beginning, we made sure to get rid of every placeholder not necessary etc. What we completely left out was the Javacript files which SharePoint uses for Ribbon, Editmode etc.
Ribbon.js we can fully rule out on mobile devices as adding or editing pages, listitems etc on the mobile device should not be possible. But the files like Core.js and Init.js is hard to determine whether or not to rule out as they are crusial for e.g. the Search Center, Social tagging, Social comments etc.
I found Chris O'Brien's excellent blog on how to compress SharePoints js files to improve loading of your website and we have been using the examples some places on the Desktop edition of the website, but are unclear about how to do so on the Mobile edition.