Speculation continues over Facebook's plans to generate even more revenue when it ultimately becomes a publicly traded company. Last week brought questions about whether the leading social media firm can resist the urge to charge membership fees or create a premium access level in the face of investor demands.

And now, inquiring minds are looking at mobile advertising as another way Facebook can cash in on its base of almost 850 million users claimed by the 8-year-old company.

It's Complicated

A published report suggests Facebook is already at work with partners creating sponsored stories and other ways to get paid content onto users' screens when they log in on-the-go.

Although Google, Apple and others are all hard at work trying to master profitable mobile ads, it's a dicey prospect because tablet and smartphone screen sizes are small, and weaker mobile devices can quickly use up their volatile memory trying to load complicated pages.

Facebook's solution could be items that show up on the users' news feed, rather than in the right corners as ads display now on the conventional Web page. The Financial Times, citing unnamed knowledgeable sources, said that "within weeks Facebook will begin showing such messages to overcome its lack of 'meaningful revenue' from mobile device users."

Twitter already features what it calls promoted Tweets. For example, the feed that results from clicking on the hashtag #superbowl produces a static Tweet from Chrysler. Google also provides clearly marked sponsored results on its search page and on YouTube.

How would an iPhone or Android user react when beer or deodorant ads start showing up among status updates from their classmates, cousins or childhood friends?

"We don't have any concrete data on mobile ad successes but I have heard that cell phone users respond positively when the trade-off is free service or a trial period associated with gaining...