During my time in China I had brought my iphone from Canada to China hoping to use it.  Unfortunately when I inserted the PRC SIM card I kept getting errors.  My boss promptly (and while mobile) posted the problem to Twitter seeking answers. Almost immedietely we started receiving tweets from people on the problem.  It was amazing to see the immediate response and get my question answered quicker and more accurately than Google search.  The answer was that no, I could not use my iPhone, but I found my new Wikipedia through the experience.