What’s Facebook’s biggest challenge nowadays? According to its Chief Executive Officer Mark Zuckerberg, it’s updating the social networking service for our increasingly mobile world, as Jon Erlichman and Christopher Palmeri of Bloomberg report:

Bringing Facebook’s features to handheld gadgets is difficult because the user experience is so different than on desktop computers, he said in an interview from the Allen & Co. media conference in Sun Valley, Idaho. Zuckerberg, meanwhile, played down the tribulations of running a newly public company.

Keep in mind Apple’s iPhone was released just five years ago. Now even innovative services like Facebook are struggling to keep up with the explosion in mobile broadband.