Mashable and other websites have enabled Google +1. The feature only shows on the full website; mobile versions don't have a +1 option.
Even this blog has +1 enabled on the normal template; but it is not on the mobile template.
As people increasingly use mobile devices to consume content and participate online, it's important to give mobile users some consideration.
Of course, it's somewhat of a moot point because Google search results with +1 recommendations don't work on the mobile version anyway.
Some sites allow you to switch to the full version of the site, thus allowing some way to +1. Some sites will kick you back to the mobile version no matter what.
Suffice it to say, there are some kinks that need straightening out with +1.
Maybe other mobile browsers will work.